Re-land of http://codereview.chromium.org/6094009 with Mac build fix....

chrome/gpu/gpu_main.cc

Index: chrome/gpu/gpu_main.cc
===================================================================
--- chrome/gpu/gpu_main.cc	(revision 70681)
+++ chrome/gpu/gpu_main.cc	(working copy)
@@ -4,9 +4,6 @@
 
 #include <stdlib.h>
 
-#include "app/app_switches.h"
-#include "app/gfx/gl/gl_context.h"
-#include "app/gfx/gl/gl_implementation.h"
 #include "app/win/scoped_com_initializer.h"
 #include "base/environment.h"
 #include "base/message_loop.h"
@@ -20,7 +17,6 @@
 #include "chrome/gpu/gpu_config.h"
 #include "chrome/gpu/gpu_process.h"
 #include "chrome/gpu/gpu_thread.h"
-#include "chrome/gpu/gpu_watchdog_thread.h"
 
 #if defined(USE_LINUX_BREAKPAD)
 #include "chrome/app/breakpad_linux.h"
@@ -28,31 +24,12 @@
 
 #if defined(OS_MACOSX)
 #include "chrome/common/chrome_application_mac.h"
-#include "chrome/common/sandbox_mac.h"
 #endif
 
 #if defined(USE_X11)
 #include "gfx/gtk_util.h"
 #endif
 
-const int kGpuTimeout = 10000;
-
-namespace {
-
-bool InitializeGpuSandbox() {
-#if defined(OS_MACOSX)
-  CommandLine* parsed_command_line = CommandLine::ForCurrentProcess();
-  SandboxInitWrapper sandbox_wrapper;
-  return sandbox_wrapper.InitializeSandbox(*parsed_command_line,
-                                           switches::kGpuProcess);
-#else
-  // TODO(port): Create GPU sandbox for linux and windows.
-  return true;
-#endif
-}
-
-}  // namespace
-
 // Main function for starting the Gpu process.
 int GpuMain(const MainFunctionParams& parameters) {
   base::Time start_time = base::Time::Now();
@@ -86,69 +63,21 @@
   gfx::GtkInitFromCommandLine(command_line);
 #endif
 
-  // Note that kNoSandbox will also disable the GPU sandbox.
-  bool no_gpu_sandbox = command_line.HasSwitch(switches::kNoGpuSandbox);
-  if (!no_gpu_sandbox) {
-    if (!InitializeGpuSandbox()) {
-      LOG(ERROR) << "Failed to initialize the GPU sandbox";
-      return EXIT_FAILURE;
-    }
-  } else {
-    LOG(ERROR) << "Running without GPU sandbox";
-  }
-
-  // Load the GL implementation and locate the bindings before starting the GPU
-  // watchdog because this can take a lot of time and the GPU watchdog might
-  // terminate the GPU process.
-  if (!gfx::GLContext::InitializeOneOff())
-    return EXIT_FAILURE;
-
-  // Do this soon before running the message loop so accurate
-  // initialization time is recorded in the GPU info. Don't do it before
-  // starting the watchdog thread since it can take a significant amount of
-  // time to collect GPU information in GpuThread::Init.
+  // We can not tolerate early returns from this code, because the
+  // detection of early return of a child process is implemented using
+  // an IPC channel error. If the IPC channel is not fully set up
+  // between the browser and GPU process, and the GPU process crashes
+  // or exits early, the browser process will never detect it.  For
+  // this reason we defer all work related to the GPU until receiving
+  // the GpuMsg_Initialize message from the browser.
   GpuProcess gpu_process;
-  GpuThread* gpu_thread = new GpuThread;
+  GpuThread* gpu_thread = new GpuThread(command_line);
   gpu_thread->Init(start_time);
   gpu_process.set_main_thread(gpu_thread);
 
-
-  // In addition to disabling the watchdog if the command line switch is
-  // present, disable it in two other cases. OSMesa is expected to run very
-  // slowly.  Also disable the watchdog on valgrind because the code is expected
-  // to run slowly in that case.
-  bool enable_watchdog =
-      !command_line.HasSwitch(switches::kDisableGpuWatchdog) &&
-      gfx::GetGLImplementation() != gfx::kGLImplementationOSMesaGL &&
-      !RunningOnValgrind();
-
-  // Disable the watchdog in debug builds because they tend to only be run by
-  // developers who will not appreciate the watchdog killing the GPU process.
-#ifndef NDEBUG
-  enable_watchdog = false;
-#endif
-
-  // Disable the watchdog for Windows. It tends to abort when the GPU process
-  // is not hung but still taking a long time to do something. Instead, the
-  // browser process displays a dialog when it notices that the child window
-  // is hung giving the user an opportunity to terminate it. This is the
-  // same mechanism used to abort hung plugins.
-#if defined(OS_WIN)
-  enable_watchdog = false;
-#endif
-
-  // Start the GPU watchdog only after anything that is expected to be time
-  // consuming has completed, otherwise the process is liable to be aborted.
-  scoped_refptr<GpuWatchdogThread> watchdog_thread;
-  if (enable_watchdog) {
-    watchdog_thread = new GpuWatchdogThread(kGpuTimeout);
-    watchdog_thread->Start();
-  }
-
   main_message_loop.Run();
 
-  if (enable_watchdog)
-    watchdog_thread->Stop();
+  gpu_thread->StopWatchdog();
 
   return 0;
 }