Implement TextureImageTransportSurface using texture mailbox

content/common/gpu/client/gl_helper.cc

Index: content/common/gpu/client/gl_helper.cc
diff --git a/content/common/gpu/client/gl_helper.cc b/content/common/gpu/client/gl_helper.cc
index ef862966fad79849a252fce6cb2f18a8043fd1aa..560882ceddf8ddd0e31efe061b171e4b443073e9 100644
--- a/content/common/gpu/client/gl_helper.cc
+++ b/content/common/gpu/client/gl_helper.cc
@@ -15,10 +15,12 @@
 #include "base/synchronization/waitable_event.h"
 #include "base/threading/thread.h"
 #include "base/threading/thread_restrictions.h"
+#include "third_party/skia/include/core/SkRegion.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebCString.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebString.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/size.h"
+#include "ui/gfx/skia_util.h"
 #include "ui/gl/gl_bindings.h"
 
 using WebKit::WebGLId;
@@ -751,4 +753,29 @@ void GLHelper::InitCopyTextToImpl() {
 
 }
 
+void GLHelper::CopySubBufferDamage(WebKit::WebGLId texture,
+                                   WebKit::WebGLId previous_texture,
+                                   const gfx::Rect& new_damage,
+                                   const gfx::Rect& old_damage) {
+  SkRegion region(RectToSkIRect(old_damage));
+  region.op(RectToSkIRect(new_damage), SkRegion::kDifference_Op);

[jonathan.backer, 2012/11/12 16:52:15]

Can we early exit if the region is empty? A common case is flash video, where
the damage rects are always the same (no need to copy). I'd prefer not to even
flush in this case.

[no sievers, 2012/11/19 20:30:44]

Done.

+  ScopedFramebuffer dst_framebuffer(context_, context_->createFramebuffer());
+  ScopedFramebufferBinder<GL_FRAMEBUFFER> framebuffer_binder(
+      context_, dst_framebuffer);
+  ScopedTextureBinder<GL_TEXTURE_2D> texture_binder(context_, texture);
+  context_->framebufferTexture2D(GL_FRAMEBUFFER,
+                                 GL_COLOR_ATTACHMENT0,
+                                 GL_TEXTURE_2D,
+                                 previous_texture,
+                                 0);
+  for (SkRegion::Iterator it(region); !it.done(); it.next()) {
+    const SkIRect& rect = it.rect();
+    context_->copyTexSubImage2D(GL_TEXTURE_2D, 0,
+                                rect.x(), rect.y(),
+                                rect.x(), rect.y(),
+                                rect.width(), rect.height());
+  }
+  context_->flush();
+}
+
 }  // namespace content