[embedder] Refactor GL texture resolution

This moves the texture resolution out of embedder.cc
and into embedder external_texture_gl.cc

Author: iskakaushik

shell/platform/embedder/embedder.cc

@@ -1146,51 +1146,13 @@ FlutterEngineResult FlutterEngineInitialize(size_t version,
                     nullptr) != nullptr) {
       external_texture_callback =
           [ptr = open_gl_config->gl_external_texture_frame_callback, user_data](
-              int64_t texture_identifier, GrDirectContext* context,
-              const SkISize& size) -> sk_sp<SkImage> {
-        FlutterOpenGLTexture texture = {};
-
-        if (!ptr(user_data, texture_identifier, size.width(), size.height(),
-                 &texture)) {
-          return nullptr;
-        }
-
-        GrGLTextureInfo gr_texture_info = {texture.target, texture.name,
-                                           texture.format};
-
-        size_t width = size.width();
-        size_t height = size.height();
-
-        if (texture.width != 0 && texture.height != 0) {
-          width = texture.width;
-          height = texture.height;
-        }
-
-        GrBackendTexture gr_backend_texture(width, height, GrMipMapped::kNo,
-                                            gr_texture_info);
-        SkImage::TextureReleaseProc release_proc = texture.destruction_callback;
-        auto image = SkImage::MakeFromTexture(
-            context,                   // context
-            gr_backend_texture,        // texture handle
-            kTopLeft_GrSurfaceOrigin,  // origin
-            kRGBA_8888_SkColorType,    // color type
-            kPremul_SkAlphaType,       // alpha type
-            nullptr,                   // colorspace
-            release_proc,              // texture release proc
-            texture.user_data          // texture release context
-        );
-
-        if (!image) {
-          // In case Skia rejects the image, call the release proc so that
-          // embedders can perform collection of intermediates.
-          if (release_proc) {
-            release_proc(texture.user_data);
-          }
-          FML_LOG(ERROR) << "Could not create external texture.";
+              int64_t texture_identifier, size_t width,
+              size_t height) -> std::unique_ptr<FlutterOpenGLTexture> {
+        FlutterOpenGLTexture* texture = new FlutterOpenGLTexture();
+        if (!ptr(user_data, texture_identifier, width, height, texture)) {
           return nullptr;
         }
-
-        return image;
+        return std::unique_ptr<FlutterOpenGLTexture>(texture);
       };
     }
   }

shell/platform/embedder/embedder_external_texture_gl.cc

@@ -5,6 +5,10 @@
 #include "flutter/shell/platform/embedder/embedder_external_texture_gl.h"
 
 #include "flutter/fml/logging.h"
+#include "third_party/skia/include/core/SkImage.h"
+#include "third_party/skia/include/core/SkSize.h"
+#include "third_party/skia/include/gpu/GrBackendSurface.h"
+#include "third_party/skia/include/gpu/GrDirectContext.h"
 
 namespace flutter {
 
@@ -23,11 +27,11 @@ void EmbedderExternalTextureGL::Paint(SkCanvas& canvas,
                                       bool freeze,
                                       GrDirectContext* context,
                                       const SkSamplingOptions& sampling) {
-  if (auto image = external_texture_callback_(
-          Id(),                                           //
-          context,                                        //
-          SkISize::Make(bounds.width(), bounds.height())  //
-          )) {
+  if (auto image =
+          ResolveTexture(Id(),                                           //
+                         context,                                        //
+                         SkISize::Make(bounds.width(), bounds.height())  //
+                         )) {
     last_image_ = image;
   }
 
@@ -40,6 +44,55 @@ void EmbedderExternalTextureGL::Paint(SkCanvas& canvas,
   }
 }
 
+sk_sp<SkImage> EmbedderExternalTextureGL::ResolveTexture(
+    int64_t texture_id,
+    GrDirectContext* context,
+    const SkISize& size) {
+  std::unique_ptr<FlutterOpenGLTexture> texture =
+      external_texture_callback_(texture_id, size.width(), size.height());
+
+  if (!texture) {
+    return nullptr;
+  }
+
+  GrGLTextureInfo gr_texture_info = {texture->target, texture->name,
+                                     texture->format};
+
+  size_t width = size.width();
+  size_t height = size.height();
+
+  if (texture->width != 0 && texture->height != 0) {
+    width = texture->width;
+    height = texture->height;
+  }
+
+  GrBackendTexture gr_backend_texture(width, height, GrMipMapped::kNo,
+                                      gr_texture_info);
+  SkImage::TextureReleaseProc release_proc = texture->destruction_callback;
+  auto image =
+      SkImage::MakeFromTexture(context,                   // context
+                               gr_backend_texture,        // texture handle
+                               kTopLeft_GrSurfaceOrigin,  // origin
+                               kRGBA_8888_SkColorType,    // color type
+                               kPremul_SkAlphaType,       // alpha type
+                               nullptr,                   // colorspace
+                               release_proc,       // texture release proc
+                               texture->user_data  // texture release context
+      );
+
+  if (!image) {
+    // In case Skia rejects the image, call the release proc so that
+    // embedders can perform collection of intermediates.
+    if (release_proc) {
+      release_proc(texture->user_data);
+    }
+    FML_LOG(ERROR) << "Could not create external texture->";
+    return nullptr;
+  }
+
+  return image;
+}
+
 // |flutter::Texture|
 void EmbedderExternalTextureGL::OnGrContextCreated() {}
 

shell/platform/embedder/embedder_external_texture_gl.h

@@ -7,27 +7,30 @@
 
 #include "flutter/common/graphics/texture.h"
 #include "flutter/fml/macros.h"
+#include "flutter/shell/platform/embedder/embedder.h"
 #include "third_party/skia/include/core/SkImage.h"
 #include "third_party/skia/include/core/SkSize.h"
 
 namespace flutter {
 
 class EmbedderExternalTextureGL : public flutter::Texture {
  public:
-  using ExternalTextureCallback =
-      std::function<sk_sp<SkImage>(int64_t texture_identifier,
-                                   GrDirectContext*,
-                                   const SkISize&)>;
+  using ExternalTextureCallback = std::function<
+      std::unique_ptr<FlutterOpenGLTexture>(int64_t, size_t, size_t)>;
 
   EmbedderExternalTextureGL(int64_t texture_identifier,
                             const ExternalTextureCallback& callback);
 
   ~EmbedderExternalTextureGL();
 
  private:
-  ExternalTextureCallback external_texture_callback_;
+  const ExternalTextureCallback& external_texture_callback_;
   sk_sp<SkImage> last_image_;
 
+  sk_sp<SkImage> ResolveTexture(int64_t texture_id,
+                                GrDirectContext* context,
+                                const SkISize& size);
+
   // |flutter::Texture|
   void Paint(SkCanvas& canvas,
              const SkRect& bounds,

shell/platform/embedder/platform_view_embedder.h

@@ -50,7 +50,7 @@ class PlatformViewEmbedder final : public PlatformView {
 
   // Create a platform view that sets up a software rasterizer.
   PlatformViewEmbedder(
-      PlatformView::Delegate& delegate,
+      const PlatformView::Delegate& delegate,
       flutter::TaskRunners task_runners,
       EmbedderSurfaceSoftware::SoftwareDispatchTable software_dispatch_table,
       PlatformDispatchTable platform_dispatch_table,
@@ -59,7 +59,7 @@ class PlatformViewEmbedder final : public PlatformView {
 #ifdef SHELL_ENABLE_GL
   // Creates a platform view that sets up an OpenGL rasterizer.
   PlatformViewEmbedder(
-      PlatformView::Delegate& delegate,
+      const PlatformView::Delegate& delegate,
       flutter::TaskRunners task_runners,
       EmbedderSurfaceGL::GLDispatchTable gl_dispatch_table,
       bool fbo_reset_after_present,
@@ -70,7 +70,7 @@ class PlatformViewEmbedder final : public PlatformView {
 #ifdef SHELL_ENABLE_METAL
   // Creates a platform view that sets up an metal rasterizer.
   PlatformViewEmbedder(
-      PlatformView::Delegate& delegate,
+      const PlatformView::Delegate& delegate,
       flutter::TaskRunners task_runners,
       std::unique_ptr<EmbedderSurfaceMetal> embedder_surface,
       PlatformDispatchTable platform_dispatch_table,