[DevTools] [PowerProfiler] Fix for browser crash with active timeline recording for capturing power.

content/browser/devtools/devtools_power_handler.cc

Index: content/browser/devtools/devtools_power_handler.cc
diff --git a/content/browser/devtools/devtools_power_handler.cc b/content/browser/devtools/devtools_power_handler.cc
index 27fdf294c6fe88cb35343980cedd6e6f56beb3f3..238c19c8251de016514436341a171ed209a51388 100644
--- a/content/browser/devtools/devtools_power_handler.cc
+++ b/content/browser/devtools/devtools_power_handler.cc
@@ -24,6 +24,9 @@ DevToolsPowerHandler::DevToolsPowerHandler() {
 }
 
 DevToolsPowerHandler::~DevToolsPowerHandler() {
+  if (PowerProfilerService::GetInstance()->HasObserver(this)) {

[qsr, 2014/06/17 16:52:48]

That feels wrong to me. If I have added myself to something, I should not have
to test that I am still an observer. If the service didn't do anything when I
register myself as an observer, it should find out by itself that and do the
right thing.

+    PowerProfilerService::GetInstance()->RemoveObserver(this);
+  }
 }
 
 void DevToolsPowerHandler::OnPowerEvent(const PowerEventVector& events) {