[DevTools] Add power profiler and power overview in timeline panel.

public/web/WebDevToolsFrontendClient.h

Index: public/web/WebDevToolsFrontendClient.h
diff --git a/public/web/WebDevToolsFrontendClient.h b/public/web/WebDevToolsFrontendClient.h
old mode 100644
new mode 100755
index 53add1c1c2b3ff40d0eccb970f030876b6dd6001..8835f92458e9db671a907f0815a2f9af0cfb80c0
--- a/public/web/WebDevToolsFrontendClient.h
+++ b/public/web/WebDevToolsFrontendClient.h
@@ -47,6 +47,11 @@ public:
 
     virtual bool isUnderTest() { return false; }
 
+    virtual void checkPowerProfileSupportedStatus() { }
+    virtual void startPowerProfile() { }
+    virtual void stopPowerProfile() { }
+    virtual void setPowerProfileResolution(unsigned) { }
+
 protected:
     virtual ~WebDevToolsFrontendClient() {}
 };