cc: Use the correct internal format for glCopyTexImage2D calls.

android_webview/browser/aw_render_thread_context_provider.cc

Index: android_webview/browser/aw_render_thread_context_provider.cc
diff --git a/android_webview/browser/aw_render_thread_context_provider.cc b/android_webview/browser/aw_render_thread_context_provider.cc
index 7385f73bd1ece7a54454ecf3e0f24e8b75808d1f..c5a585aee0f0c30213711b680bb6eddf4341f9e6 100644
--- a/android_webview/browser/aw_render_thread_context_provider.cc
+++ b/android_webview/browser/aw_render_thread_context_provider.cc
@@ -75,6 +75,11 @@ AwRenderThreadContextProvider::~AwRenderThreadContextProvider() {
     gr_context_->releaseResourcesAndAbandonContext();
 }
 
+uint32_t AwRenderThreadContextProvider::GetCopyTextureInternalFormat() {
+  // The attributes used in the constructor included an alpha channel.
+  return GL_RGBA;
+}
+
 bool AwRenderThreadContextProvider::BindToCurrentThread() {
   // This is called on the thread the context will be used.
   DCHECK(main_thread_checker_.CalledOnValidThread());