Created multi-process-friendly PowerMonitor interface.

content/common/gpu/client/gpu_channel_host.cc

Index: content/common/gpu/client/gpu_channel_host.cc
diff --git a/content/common/gpu/client/gpu_channel_host.cc b/content/common/gpu/client/gpu_channel_host.cc
index fc6e89dfda4755978ae9c1c46d797591f65ee73b..64c0c7a626a0335c655d4bac8cce0d0db0c37637 100644
--- a/content/common/gpu/client/gpu_channel_host.cc
+++ b/content/common/gpu/client/gpu_channel_host.cc
@@ -11,9 +11,11 @@
 #include "base/message_loop.h"
 #include "base/message_loop/message_loop_proxy.h"
 #include "base/posix/eintr_wrapper.h"
+#include "base/power_monitor/power_monitor.h"
 #include "base/threading/thread_restrictions.h"
 #include "content/common/gpu/client/command_buffer_proxy_impl.h"
 #include "content/common/gpu/gpu_messages.h"
+#include "content/common/power_monitor_service.h"
 #include "googleurl/src/gurl.h"
 #include "gpu/command_buffer/common/mailbox.h"
 #include "ipc/ipc_sync_message_filter.h"
@@ -52,8 +54,13 @@ GpuChannelHost::GpuChannelHost(GpuChannelHostFactory* factory,
     : factory_(factory),
       client_id_(client_id),
       gpu_host_id_(gpu_host_id),
-      gpu_info_(gpu_info) {
+      gpu_info_(gpu_info),
+      power_monitor_service_(new PowerMonitorService(this)) {
   next_transfer_buffer_id_.GetNext();
+
+  base::PowerMonitor* power_monitor = base::PowerMonitor::Get();
+  if (power_monitor)
+    power_monitor->AddObserver(power_monitor_service_.get());

[Ken Russell (switch to Gerrit), 2013/06/24 22:54:38]

Unless I'm misremembering and misreading the code, GpuChannelHosts are
instantiated both in the browser process and renderer processes. See
RenderThreadImpl::EstablishGpuChannelSync and
BrowserGpuChannelHostFactory::EstablishGpuChannelSync . Did you run into this
problem and/or expect this? I don't think the renderer process should attempt to
instantiate any power monitor-related objects. If the code deliberately runs
differently in the browser and renderer processes then big comments should be
added to the power_monitor_service_ field in the header pointing out that it's
only used in the browser, and the PowerMontiorService shouldn't even be created
if base::PowerMonitor::Get() returns NULL.

 }
 
 void GpuChannelHost::Connect(const IPC::ChannelHandle& channel_handle) {