Reland 98392 - Split WebGraphicsContext3DCommandBufferImpl::initialize() into two stages.

content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.cc

Index: content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.cc
===================================================================
--- content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.cc	(revision 99636)
+++ content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.cc	(working copy)
@@ -21,6 +21,7 @@
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
+#include "base/synchronization/lock.h"
 #include "content/common/content_switches.h"
 #include "content/renderer/gpu/gpu_channel_host.h"
 #include "content/renderer/render_thread.h"
@@ -32,6 +33,8 @@
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebView.h"
 #include "webkit/glue/gl_bindings_skia_cmd_buffer.h"
 
+static base::LazyInstance<base::Lock>
+    g_all_shared_contexts_lock(base::LINKER_INITIALIZED);
 static base::LazyInstance<std::set<WebGraphicsContext3DCommandBufferImpl*> >
     g_all_shared_contexts(base::LINKER_INITIALIZED);
 
@@ -55,7 +58,10 @@
 
 WebGraphicsContext3DCommandBufferImpl::
     ~WebGraphicsContext3DCommandBufferImpl() {
-  g_all_shared_contexts.Pointer()->erase(this);
+  {
+    base::AutoLock lock(g_all_shared_contexts_lock.Get());
+    g_all_shared_contexts.Pointer()->erase(this);
+  }
   delete context_;
 }
 
@@ -71,85 +77,102 @@
     WebGraphicsContext3D::Attributes attributes,
     WebKit::WebView* web_view,
     bool render_directly_to_web_view) {
+  DCHECK(!context_);
   TRACE_EVENT0("gpu", "WebGfxCtx3DCmdBfrImpl::initialize");
   RenderThread* render_thread = RenderThread::current();
   if (!render_thread)
     return false;
-  GpuChannelHost* host = render_thread->EstablishGpuChannelSync(
+  host_ = render_thread->EstablishGpuChannelSync(
     content::
       CAUSE_FOR_GPU_LAUNCH_WEBGRAPHICSCONTEXT3DCOMMANDBUFFERIMPL_INITIALIZE);
-  if (!host)
+  if (!host_)
     return false;
-  DCHECK(host->state() == GpuChannelHost::kConnected);
+  DCHECK(host_->state() == GpuChannelHost::kConnected);
 
+  const GPUInfo& gpu_info = host_->gpu_info();
+  UMA_HISTOGRAM_ENUMERATION(
+      "GPU.WebGraphicsContext3D_Init_CanLoseContext",
+      attributes.canRecoverFromContextLoss * 2 + gpu_info.can_lose_context,
+      4);
+  if (attributes.canRecoverFromContextLoss == false) {
+    if (gpu_info.can_lose_context)
+      return false;
+  }
+
+  if (web_view && web_view->mainFrame())
+    active_url_ = GURL(web_view->mainFrame()->document().url());
+
+  attributes_ = attributes;
+  render_directly_to_web_view_ = render_directly_to_web_view;
+  if (render_directly_to_web_view_) {
+    RenderView* render_view = RenderView::FromWebView(web_view);
+    if (!render_view)
+      return false;
+    render_view_routing_id_ = render_view->routing_id();
+#ifndef WTF_USE_THREADED_COMPOSITING
+    web_view_ = web_view;
+#endif
+  }
+  return true;
+}
+
+bool WebGraphicsContext3DCommandBufferImpl::MaybeInitializeGL() {
+  if (context_)
+    return true;
+
+  TRACE_EVENT0("gpu", "WebGfxCtx3DCmdBfrImpl::MaybeInitializeGL");
+
   // Convert WebGL context creation attributes into RendererGLContext / EGL size
   // requests.
-  const int alpha_size = attributes.alpha ? 8 : 0;
-  const int depth_size = attributes.depth ? 24 : 0;
-  const int stencil_size = attributes.stencil ? 8 : 0;
-  const int samples = attributes.antialias ? 4 : 0;
-  const int sample_buffers = attributes.antialias ? 1 : 0;
+  const int alpha_size = attributes_.alpha ? 8 : 0;
+  const int depth_size = attributes_.depth ? 24 : 0;
+  const int stencil_size = attributes_.stencil ? 8 : 0;
+  const int samples = attributes_.antialias ? 4 : 0;
+  const int sample_buffers = attributes_.antialias ? 1 : 0;
   const int32 attribs[] = {
     RendererGLContext::ALPHA_SIZE, alpha_size,
     RendererGLContext::DEPTH_SIZE, depth_size,
     RendererGLContext::STENCIL_SIZE, stencil_size,
     RendererGLContext::SAMPLES, samples,
     RendererGLContext::SAMPLE_BUFFERS, sample_buffers,
-    RendererGLContext::SHARE_RESOURCES, attributes.shareResources ? 1 : 0,
+    RendererGLContext::SHARE_RESOURCES, attributes_.shareResources ? 1 : 0,
     RendererGLContext::BIND_GENERATES_RESOURCES, 0,
     RendererGLContext::NONE,
   };
 
-  const char* preferred_extensions = attributes.noExtensions ?
+  const char* preferred_extensions = attributes_.noExtensions ?
       kWebGLPreferredGLExtensions : "*";
 
-  const GPUInfo& gpu_info = host->gpu_info();
-  UMA_HISTOGRAM_ENUMERATION(
-      "GPU.WebGraphicsContext3D_Init_CanLoseContext",
-      attributes.canRecoverFromContextLoss * 2 + gpu_info.can_lose_context,
-      4);
-  if (attributes.canRecoverFromContextLoss == false) {
-    if (gpu_info.can_lose_context)
-      return false;
-  }
+  // We need to lock g_all_shared_contexts until after RendererGLContext::Create
+  // to ensure that the context we picked for our share group isn't deleted.
+  // (There's also a lock in our destructor.)
+  {
+    base::AutoLock lock(g_all_shared_contexts_lock.Get());
+    RendererGLContext* share_group = NULL;
+    if (attributes_.shareResources) {
+      share_group = g_all_shared_contexts.Pointer()->empty() ?
+          NULL : (*g_all_shared_contexts.Pointer()->begin())->context_;
+    }
 
-  GURL active_url;
-  if (web_view && web_view->mainFrame())
-    active_url = GURL(web_view->mainFrame()->document().url());
-
-  RendererGLContext* share_group = NULL;
-  if (attributes.shareResources) {
-    share_group = g_all_shared_contexts.Pointer()->empty() ?
-        NULL : (*g_all_shared_contexts.Pointer()->begin())->context_;
+    if (render_directly_to_web_view_) {
+      context_ = RendererGLContext::CreateViewContext(
+          host_,
+          render_view_routing_id_,
+          share_group,
+          preferred_extensions,
+          attribs,
+          active_url_);
+    } else {
+      context_ = RendererGLContext::CreateOffscreenContext(
+          host_,
+          gfx::Size(1, 1),
+          share_group,
+          preferred_extensions,
+          attribs,
+          active_url_);
+    }
   }
 
-  render_directly_to_web_view_ = render_directly_to_web_view;
-  if (render_directly_to_web_view) {
-#ifndef WTF_USE_THREADED_COMPOSITING
-    RenderView* renderview = RenderView::FromWebView(web_view);
-    if (!renderview)
-      return false;
-    web_view_ = web_view;
-#endif
-    context_ = RendererGLContext::CreateViewContext(
-        host,
-        renderview->routing_id(),
-        share_group,
-        preferred_extensions,
-        attribs,
-        active_url);
-  } else {
-    context_ = RendererGLContext::CreateOffscreenContext(
-        host,
-        gfx::Size(1, 1),
-        share_group,
-        preferred_extensions,
-        attribs,
-        active_url);
-#ifndef WTF_USE_THREADED_COMPOSITING
-    web_view_ = NULL;
-#endif
-  }
   if (!context_)
     return false;
 
@@ -166,7 +189,6 @@
 
   // Set attributes_ from created offscreen context.
   {
-    attributes_ = attributes;
     GLint alpha_bits = 0;
     getIntegerv(GL_ALPHA_BITS, &alpha_bits);
     attributes_.alpha = alpha_bits > 0;
@@ -181,13 +203,17 @@
     attributes_.antialias = samples > 0;
   }
 
-  if (attributes.shareResources)
+  if (attributes_.shareResources) {
+    base::AutoLock lock(g_all_shared_contexts_lock.Get());
     g_all_shared_contexts.Pointer()->insert(this);
+  }
 
   return true;
 }
 
 bool WebGraphicsContext3DCommandBufferImpl::makeContextCurrent() {
+  if (!MaybeInitializeGL())
+    return false;
   return RendererGLContext::MakeCurrent(context_);
 }
 
@@ -212,7 +238,6 @@
 }
 
 WebGLId WebGraphicsContext3DCommandBufferImpl::getPlatformTextureId() {
-  DCHECK(context_);
   return context_->GetParentTextureId();
 }