Hide ContentClient getters from embedders so that they they don't reuse content's embedder API. The…

content/shell/shell_content_renderer_client.cc

Index: content/shell/shell_content_renderer_client.cc
===================================================================
--- content/shell/shell_content_renderer_client.cc	(revision 192622)
+++ content/shell/shell_content_renderer_client.cc	(working copy)
@@ -42,7 +42,17 @@
 
 namespace content {
 
+namespace {
+ShellContentRendererClient* g_renderer_client;
+}
+
+ShellContentRendererClient* ShellContentRendererClient::Get() {
+  return g_renderer_client;
+}
+
 ShellContentRendererClient::ShellContentRendererClient() {
+  DCHECK(!g_renderer_client);
+  g_renderer_client = this;
   if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kDumpRenderTree)) {
     EnableWebTestProxyCreation(
         base::Bind(&ShellContentRendererClient::WebTestProxyCreated,
@@ -51,6 +61,7 @@
 }
 
 ShellContentRendererClient::~ShellContentRendererClient() {
+  g_renderer_client = NULL;
 }
 
 void ShellContentRendererClient::LoadHyphenDictionary(