Asynchronously launches the GPU process.

- First renderer process sends IPC to browser process causing it to prelaunch the GPU process.
- IPC channel is subsequently established.
- If EstablishAsyncChannelSync is not called during this period, it will not block.
- Future renderer processes simply asynchronously establish the IPC channel.
- This also causes the GPU process to be relaunched if it crashed.

TEST=try, observed that GPU process launches even for pages without 3D content
BUG=none

Review URL: http://codereview.chromium.org/2952005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@52152 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 14 insertions, 0 deletions

diff --git a/chrome/browser/renderer_host/browser_render_process_host.cc b/chrome/browser/renderer_host/browser_render_process_host.cc
index 411a597..e945628 100644
--- a/chrome/browser/renderer_host/browser_render_process_host.cc
+++ b/chrome/browser/renderer_host/browser_render_process_host.cc
@@ -575,6 +575,7 @@ void BrowserRenderProcessHost::PropagateBrowserCommandLineToRenderer(
     switches::kRemoteShellPort,
     switches::kEnablePepperTesting,
     switches::kEnableChromoting,
+    switches::kPrelaunchGpuProcess,
   };
 
   for (size_t i = 0; i < arraysize(switch_names); ++i) {
diff --git a/chrome/common/chrome_switches.cc b/chrome/common/chrome_switches.cc
index 83caf08..127baac 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -674,6 +674,10 @@ const char kPluginStartupDialog[]           = "plugin-startup-dialog";
 // possibly be used for connections.
 const char kPreconnectDespiteProxy[]        = "preconnect-despite-proxy";
 
+// Establishes a channel to the GPU process asynchronously and (re)launches it
+// if necessary when a renderer process starts.
+const char kPrelaunchGpuProcess[]           = "prelaunch-gpu-process";
+
 // Prints the pages on the screen.
 const char kPrint[]                         = "print";
 
diff --git a/chrome/common/chrome_switches.h b/chrome/common/chrome_switches.h
index 87755e7..558189d 100644
--- a/chrome/common/chrome_switches.h
+++ b/chrome/common/chrome_switches.h
@@ -200,6 +200,7 @@ extern const char kPluginPath[];
 extern const char kPluginProcess[];
 extern const char kPluginStartupDialog[];
 extern const char kPreconnectDespiteProxy[];
+extern const char kPrelaunchGpuProcess[];
 extern const char kPrint[];
 extern const char kProcessPerSite[];
 extern const char kProcessPerTab[];
diff --git a/chrome/renderer/render_thread.cc b/chrome/renderer/render_thread.cc
index 30be754..95588c8 100644
--- a/chrome/renderer/render_thread.cc
+++ b/chrome/renderer/render_thread.cc
@@ -253,6 +253,14 @@ void RenderThread::Init() {
   suicide_on_channel_error_filter_ = new SuicideOnChannelErrorFilter;
   AddFilter(suicide_on_channel_error_filter_.get());
 #endif
+
+  // Establish a channel to the GPU process asynchronously if requested. If the
+  // channel is established in time, EstablishGpuChannelSync will not block when
+  // it is later called.
+  if (CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kPrelaunchGpuProcess)) {
+    EstablishGpuChannel();
+  }
 }
 
 RenderThread::~RenderThread() {