Reland 93106 - Reparenting of RendererGLContexts supports going from no parent to having a parent.

RendererGLContext::SetParent is a no-op if the parent did not change to avoid a redundant sync IPC.

Added SetParentContext to WebGraphicsContext3DCommandBufferImpl. WebKit change to follow.

Original review: http://codereview.chromium.org/7237009

A patch that this was dependent on was reverting, causing this one to break 2D canvas. The patch is relanded. Relanding this one as well.
Review URL: http://codereview.chromium.org/7488001

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@93677 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 13 insertions, 20 deletions

diff --git a/content/renderer/gpu/renderer_gl_context.cc b/content/renderer/gpu/renderer_gl_context.cc
index bf2d100..4937a46 100644
--- a/content/renderer/gpu/renderer_gl_context.cc
+++ b/content/renderer/gpu/renderer_gl_context.cc
@@ -224,6 +224,9 @@ RendererGLContext* RendererGLContext::CreateOffscreenContext(
 }
 
 bool RendererGLContext::SetParent(RendererGLContext* new_parent) {
+  if (parent_.get() == new_parent)
+    return true;
+
   // Allocate a texture ID with respect to the parent and change the parent.
   uint32 new_parent_texture_id = 0;
   if (command_buffer_) {
diff --git a/content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.cc b/content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.cc
index 79d7616..7836744 100644
--- a/content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.cc
+++ b/content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.cc
@@ -106,7 +106,6 @@ bool WebGraphicsContext3DCommandBufferImpl::initialize(
   if (web_view && web_view->mainFrame())
     active_url = GURL(web_view->mainFrame()->document().url());
 
-  RendererGLContext* parent_context = NULL;
   if (render_directly_to_web_view) {
     RenderView* renderview = RenderView::FromWebView(web_view);
     if (!renderview)
@@ -125,22 +124,6 @@ bool WebGraphicsContext3DCommandBufferImpl::initialize(
               &WebGraphicsContext3DCommandBufferImpl::OnSwapBuffersComplete));
     }
   } else {
-    bool compositing_enabled = !CommandLine::ForCurrentProcess()->HasSwitch(
-        switches::kDisableAcceleratedCompositing);
-    // If GPU compositing is enabled we need to create a GL context that shares
-    // resources with the compositor's context.
-    if (compositing_enabled) {
-      // Asking for the WebGraphicsContext3D on the WebView will force one to
-      // be created if it doesn't already exist. When the compositor is created
-      // for the view it will use the same context.
-      WebKit::WebGraphicsContext3D* view_context =
-          web_view->graphicsContext3D();
-      if (view_context) {
-        WebGraphicsContext3DCommandBufferImpl* context_impl =
-            static_cast<WebGraphicsContext3DCommandBufferImpl*>(view_context);
-        parent_context = context_impl->context_;
-      }
-    }
     context_ = RendererGLContext::CreateOffscreenContext(
         host,
         gfx::Size(1, 1),
@@ -152,9 +135,6 @@ bool WebGraphicsContext3DCommandBufferImpl::initialize(
   if (!context_)
     return false;
 
-  if (!context_->SetParent(parent_context))
-    return false;
-
   gl_ = context_->GetImplementation();
   context_->SetContextLostCallback(
       NewCallback(this,
@@ -202,6 +182,14 @@ bool WebGraphicsContext3DCommandBufferImpl::isGLES2Compliant() {
   return true;
 }
 
+bool WebGraphicsContext3DCommandBufferImpl::setParentContext(
+    WebGraphicsContext3D* parent_context) {
+  WebGraphicsContext3DCommandBufferImpl* parent_context_impl =
+      static_cast<WebGraphicsContext3DCommandBufferImpl*>(parent_context);
+  return context_->SetParent(
+      parent_context_impl ? parent_context_impl->context() : NULL);
+}
+
 WebGLId WebGraphicsContext3DCommandBufferImpl::getPlatformTextureId() {
   DCHECK(context_);
   return context_->GetParentTextureId();
diff --git a/content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.h b/content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.h
index 5411502..e291c82 100644
--- a/content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.h
+++ b/content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.h
@@ -64,6 +64,8 @@ class WebGraphicsContext3DCommandBufferImpl
 
   virtual bool isGLES2Compliant();
 
+  virtual bool setParentContext(WebGraphicsContext3D* parent_context);
+
   virtual void reshape(int width, int height);
 
   virtual bool readBackFramebuffer(unsigned char* pixels, size_t buffer_size);