Forward handling of low-mem message to the content renderer client. Add APIs to handle this case.

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 ee7db8e0a72e4b8a568906070be85010264247f5..458202c702eb2ac51216518c144b6fcd10e8c9ed 100644
--- a/chrome/renderer/chrome_content_renderer_client.cc
+++ b/chrome/renderer/chrome_content_renderer_client.cc
@@ -20,6 +20,9 @@
 #include "chrome/common/extensions/extension_constants.h"
 #include "chrome/common/extensions/extension_set.h"
 #include "chrome/common/jstemplate_builder.h"
+#include "content/common/notification_details.h"
+#include "content/common/notification_service.h"
+#include "content/common/notification_source.h"
 #include "chrome/common/render_messages.h"
 #include "chrome/common/url_constants.h"
 #include "chrome/renderer/autofill/autofill_agent.h"
@@ -204,6 +207,9 @@ void ChromeContentRendererClient::RenderThreadStarted() {
   // chrome-extension: resources shouldn't trigger insecure content warnings.
   WebString extension_scheme(ASCIIToUTF16(chrome::kExtensionScheme));
   WebSecurityPolicy::registerURLSchemeAsSecure(extension_scheme);
+
+  // Get updates when we need to purge memory.
+  registrar_.Add(this, content::NOTIFICATION_PURGE_MEMORY, Source<void>(NULL));
 }
 
 void ChromeContentRendererClient::RenderViewCreated(RenderView* render_view) {
@@ -214,7 +220,8 @@ void ChromeContentRendererClient::RenderViewCreated(RenderView* render_view) {
   new PageLoadHistograms(render_view, histogram_snapshots_.get());
   new PrintWebViewHelper(render_view);
   new SearchBox(render_view);
-  new SpellCheckProvider(render_view, spellcheck_.get());
+  spellcheck_provider_.reset(new SpellCheckProvider(render_view,
+                                                    spellcheck_.get()));
 #if defined(ENABLE_SAFE_BROWSING)
   safe_browsing::MalwareDOMDetails::Create(render_view);
 #endif
@@ -624,4 +631,22 @@ bool ChromeContentRendererClient::CrossesExtensionExtents(WebFrame* frame,
   return !extensions->InSameExtent(old_url, new_url);
 }
 
+void ChromeContentRendererClient::Observe(int type,
+                                          const NotificationSource& source,
+                                          const NotificationDetails& details) {
+  if (type == content::NOTIFICATION_PURGE_MEMORY)
+    ResetSpellCheck();
+}
+
+void ChromeContentRendererClient::ResetSpellCheck() {
+  LOG(INFO) << "Resetting spellcheck in renderer client";
+  RenderThread* thread = RenderThread::current();
+  if (spellcheck_.get())
+    thread->RemoveObserver(spellcheck_.get());
+  spellcheck_.reset(new SpellCheck());
+  thread->AddObserver(spellcheck_.get());
+  if (spellcheck_provider_.get())
+    spellcheck_provider_->SetSpellCheck(spellcheck_.get());
+}
+
 }  // namespace chrome