Add a gyp flag to allow removing dependency on ppapi.

chrome/renderer/chrome_content_renderer_client.cc

Index: chrome/renderer/chrome_content_renderer_client.cc
diff --git a/chrome/renderer/chrome_content_renderer_client.cc b/chrome/renderer/chrome_content_renderer_client.cc
index f989131bb72e8c699616a72676257c51e18f1a0c..d600d5c5801f23d1afb28f792c393980b6c4953b 100644
--- a/chrome/renderer/chrome_content_renderer_client.cc
+++ b/chrome/renderer/chrome_content_renderer_client.cc
@@ -301,7 +301,10 @@ void ChromeContentRendererClient::RenderViewCreated(
       render_view, content_settings, chrome_observer_.get(),
       extension_dispatcher_.get(), translate);
 
+#if defined(ENABLE_PPAPI)
   new PepperHelper(render_view);
+#endif
+
   // FaviconHelper will delete itself when render_view is destroyed.
   new FaviconHelper(render_view);
   // Used only for testing/automation.
@@ -1021,7 +1024,9 @@ bool ChromeContentRendererClient::IsOtherExtensionWithWebRequestInstalled() {
 
 void ChromeContentRendererClient::RegisterPPAPIInterfaceFactories(
     webkit::ppapi::PpapiInterfaceFactoryManager* factory_manager) {
+#if defined(ENABLE_PPAPI)
   factory_manager->RegisterFactory(ChromePPAPIInterfaceFactory);
+#endif
 }
 
 }  // namespace chrome