webgl: optimize webgl.texSubImage2D(video) path.

media/blink/skcanvas_video_renderer.cc

Index: media/blink/skcanvas_video_renderer.cc
diff --git a/media/blink/skcanvas_video_renderer.cc b/media/blink/skcanvas_video_renderer.cc
index 90297f7dc8f1db1321143a86659b1af5ab49357c..4b715b2575e7a838bdaba2c03075f8958e142b44 100644
--- a/media/blink/skcanvas_video_renderer.cc
+++ b/media/blink/skcanvas_video_renderer.cc
@@ -154,8 +154,8 @@ skia::RefPtr<SkImage> NewSkImageFromVideoFrameNative(
     DCHECK(source_texture);
     gl->BindTexture(GL_TEXTURE_2D, source_texture);
     SkCanvasVideoRenderer::CopyVideoFrameSingleTextureToGLTexture(
-        gl, video_frame, source_texture, GL_RGBA, GL_UNSIGNED_BYTE, true,
-        false);
+        gl, video_frame, GL_TEXTURE_2D, source_texture, GL_RGBA,
+        GL_UNSIGNED_BYTE, 0, true, false);
   } else {
     gl->WaitSyncPointCHROMIUM(mailbox_holder.sync_point);
     source_texture = gl->CreateAndConsumeTextureCHROMIUM(
@@ -172,6 +172,59 @@ skia::RefPtr<SkImage> NewSkImageFromVideoFrameNative(
       SkImage::NewFromAdoptedTexture(context_3d.gr_context, desc));
 }
 
+void CopyVideoFrameSingleTextureToGLTextureInternal(
+    gpu::gles2::GLES2Interface* gl,
+    VideoFrame* video_frame,
+    bool is_full_copy,
+    unsigned int target,
+    unsigned int texture,
+    unsigned int internal_format,
+    unsigned int type,
+    int level,
+    int xoffset,
+    int yoffset,
+    bool premultiply_alpha,
+    bool flip_y) {
+  DCHECK(video_frame);
+  DCHECK(video_frame->HasTextures());
+  DCHECK_EQ(1u, VideoFrame::NumPlanes(video_frame->format()));
+
+  const gpu::MailboxHolder& mailbox_holder = video_frame->mailbox_holder(0);
+  DCHECK(mailbox_holder.texture_target == GL_TEXTURE_2D ||
+         mailbox_holder.texture_target == GL_TEXTURE_RECTANGLE_ARB ||
+         mailbox_holder.texture_target == GL_TEXTURE_EXTERNAL_OES)
+      << mailbox_holder.texture_target;
+
+  gl->WaitSyncPointCHROMIUM(mailbox_holder.sync_point);
+  uint32 source_texture = gl->CreateAndConsumeTextureCHROMIUM(
+      mailbox_holder.texture_target, mailbox_holder.mailbox.name);
+
+  // The video is stored in a unmultiplied format, so premultiply
+  // if necessary.
+  // Application itself needs to take care of setting the right |flip_y|
+  // value down to get the expected result.
+  // "flip_y == true" means to reverse the video orientation while
+  // "flip_y == false" means to keep the intrinsic orientation.
+  if (is_full_copy) {
+    DCHECK(!xoffset && !yoffset);
+    gl->CopyTextureCHROMIUM(target, source_texture, texture, internal_format,
+                            type, flip_y, premultiply_alpha, false);
+  } else {
+    DCHECK_EQ(static_cast<unsigned int>(GL_FALSE), internal_format);
+    DCHECK_EQ(static_cast<unsigned int>(GL_FALSE), type);
+    gl->CopySubTextureCHROMIUM(
+        target, source_texture, texture, xoffset, yoffset, 0, 0,
+        video_frame->natural_size().width(),
+        video_frame->natural_size().height(), flip_y, premultiply_alpha, false);
+  }
+
+  gl->DeleteTextures(1, &source_texture);
+  gl->Flush();
+
+  SyncPointClientImpl client(gl);
+  video_frame->UpdateReleaseSyncPoint(&client);
+}
+
 }  // anonymous namespace
 
 // Generates an RGB image from a VideoFrame. Convert YUV to RGB plain on GPU.
@@ -533,40 +586,32 @@ void SkCanvasVideoRenderer::ConvertVideoFrameToRGBPixels(
 void SkCanvasVideoRenderer::CopyVideoFrameSingleTextureToGLTexture(
     gpu::gles2::GLES2Interface* gl,
     VideoFrame* video_frame,
+    unsigned int target,
     unsigned int texture,
     unsigned int internal_format,
     unsigned int type,
+    int level,
     bool premultiply_alpha,
     bool flip_y) {
-  DCHECK(video_frame);
-  DCHECK(video_frame->HasTextures());
-  DCHECK_EQ(1u, VideoFrame::NumPlanes(video_frame->format()));
-
-  const gpu::MailboxHolder& mailbox_holder = video_frame->mailbox_holder(0);
-  DCHECK(mailbox_holder.texture_target == GL_TEXTURE_2D ||
-         mailbox_holder.texture_target == GL_TEXTURE_RECTANGLE_ARB ||
-         mailbox_holder.texture_target == GL_TEXTURE_EXTERNAL_OES)
-      << mailbox_holder.texture_target;
-
-  gl->WaitSyncPointCHROMIUM(mailbox_holder.sync_point);
-  uint32 source_texture = gl->CreateAndConsumeTextureCHROMIUM(
-      mailbox_holder.texture_target, mailbox_holder.mailbox.name);
-
-  // The video is stored in a unmultiplied format, so premultiply
-  // if necessary.
-  // Application itself needs to take care of setting the right |flip_y|
-  // value down to get the expected result.
-  // "flip_y == true" means to reverse the video orientation while
-  // "flip_y == false" means to keep the intrinsic orientation.
-  gl->CopyTextureCHROMIUM(GL_TEXTURE_2D, source_texture, texture,
-                          internal_format, type,
-                          flip_y, premultiply_alpha, false);
-
-  gl->DeleteTextures(1, &source_texture);
-  gl->Flush();
+  CopyVideoFrameSingleTextureToGLTextureInternal(
+      gl, video_frame, true, target, texture, internal_format, type, level, 0,
+      0, premultiply_alpha, flip_y);
+}
 
-  SyncPointClientImpl client(gl);
-  video_frame->UpdateReleaseSyncPoint(&client);
+// static
+void SkCanvasVideoRenderer::CopySubVideoFrameSingleTextureToGLTexture(
+    gpu::gles2::GLES2Interface* gl,
+    VideoFrame* video_frame,
+    unsigned int target,
+    unsigned int texture,
+    int level,
+    int xoffset,
+    int yoffset,
+    bool premultiply_alpha,
+    bool flip_y) {
+  CopyVideoFrameSingleTextureToGLTextureInternal(
+      gl, video_frame, false, target, texture, GL_FALSE, GL_FALSE, level,
+      xoffset, yoffset, premultiply_alpha, flip_y);
 }
 
 void SkCanvasVideoRenderer::ResetCache() {