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

Found from Coverity CID=16390

R=jam@chromium.org
BUG=
TEST=none


Review URL: http://codereview.chromium.org/7222023

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@95896 0039d316-1c4b-4281-b951-d872f2087c98

chrome/renderer/chrome_content_renderer_client.cc

@@ -152,7 +152,7 @@ ChromeContentRendererClient::~ChromeContentRendererClient() {
 }
 
 void ChromeContentRendererClient::RenderThreadStarted() {
-  chrome_observer_.reset(new ChromeRenderProcessObserver());
+  chrome_observer_.reset(new ChromeRenderProcessObserver(this));
   extension_dispatcher_.reset(new ExtensionDispatcher());
   histogram_snapshots_.reset(new RendererHistogramSnapshots());
   net_predictor_.reset(new RendererNetPredictor());
@@ -215,7 +215,7 @@ 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_ = new SpellCheckProvider(render_view, spellcheck_.get());
 #if defined(ENABLE_SAFE_BROWSING)
   safe_browsing::MalwareDOMDetails::Create(render_view);
 #endif
@@ -692,4 +692,16 @@ bool ChromeContentRendererClient::CrossesExtensionExtents(WebFrame* frame,
   return !extensions->InSameExtent(old_url, new_url);
 }
 
+void ChromeContentRendererClient::OnPurgeMemory() {
+  DVLOG(1) << "Resetting spellcheck in renderer client";
+  RenderThread* thread = RenderThread::current();
+  if (spellcheck_.get())
+    thread->RemoveObserver(spellcheck_.get());
+  SpellCheck* new_spellcheck = new SpellCheck();
+  if (spellcheck_provider_)
+    spellcheck_provider_->SetSpellCheck(new_spellcheck);
+  spellcheck_.reset(new_spellcheck);
+  thread->AddObserver(new_spellcheck);
+}
+
 }  // namespace chrome

chrome/renderer/chrome_content_renderer_client.h

@@ -15,6 +15,7 @@ class ExtensionDispatcher;
 class RendererHistogramSnapshots;
 class RendererNetPredictor;
 class SpellCheck;
+class SpellCheckProvider;
 class VisitedLinkSlave;
 
 namespace safe_browsing {
@@ -73,6 +74,10 @@ class ChromeContentRendererClient : public content::ContentRendererClient {
   // For testing.
   void SetExtensionDispatcher(ExtensionDispatcher* extension_dispatcher);
 
+  // Called in low-memory conditions to dump the memory used by the spellchecker
+  // and start over.
+  void OnPurgeMemory();
+
  private:
   WebKit::WebPlugin* CreatePluginImpl(
       RenderView* render_view,
@@ -99,6 +104,9 @@ class ChromeContentRendererClient : public content::ContentRendererClient {
   scoped_ptr<RendererHistogramSnapshots> histogram_snapshots_;
   scoped_ptr<RendererNetPredictor> net_predictor_;
   scoped_ptr<SpellCheck> spellcheck_;
+  // The SpellCheckProvider is a RenderViewObserver, and handles its own
+  // destruction.
+  SpellCheckProvider* spellcheck_provider_;
   scoped_ptr<VisitedLinkSlave> visited_link_slave_;
   scoped_ptr<safe_browsing::PhishingClassifierFilter> phishing_classifier_;
 };

chrome/renderer/chrome_render_process_observer.cc

@@ -17,6 +17,7 @@
 #include "chrome/common/extensions/extension_localization_peer.h"
 #include "chrome/common/net/net_resource_provider.h"
 #include "chrome/common/render_messages.h"
+#include "chrome/renderer/chrome_content_renderer_client.h"
 #include "chrome/renderer/content_settings_observer.h"
 #include "chrome/renderer/security_filter_peer.h"
 #include "content/common/resource_dispatcher.h"
@@ -305,7 +306,9 @@ class ShutdownDetector : public base::PlatformThread::Delegate {
 
 bool ChromeRenderProcessObserver::is_incognito_process_ = false;
 
-ChromeRenderProcessObserver::ChromeRenderProcessObserver() {
+ChromeRenderProcessObserver::ChromeRenderProcessObserver(
+    chrome::ChromeContentRendererClient* client)
+    : client_(client) {
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
   if (command_line.HasSwitch(switches::kEnableWatchdog)) {
     // TODO(JAR): Need to implement renderer IO msgloop watchdog.
@@ -502,4 +505,7 @@ void ChromeRenderProcessObserver::OnPurgeMemory() {
   // Tell tcmalloc to release any free pages it's still holding.
   MallocExtension::instance()->ReleaseFreeMemory();
 #endif
+
+  if (client_)
+    client_->OnPurgeMemory();
 }

chrome/renderer/chrome_render_process_observer.h

@@ -12,6 +12,10 @@
 #include "base/memory/scoped_ptr.h"
 #include "content/renderer/render_process_observer.h"
 
+namespace chrome {
+class ChromeContentRendererClient;
+}
+
 class GURL;
 class ResourceDispatcherDelegate;
 struct ContentSettings;
@@ -22,7 +26,8 @@ struct ContentSettings;
 // observer.
 class ChromeRenderProcessObserver : public RenderProcessObserver {
  public:
-  ChromeRenderProcessObserver();
+  explicit ChromeRenderProcessObserver(
+      chrome::ChromeContentRendererClient* client);
   virtual ~ChromeRenderProcessObserver();
 
   static bool is_incognito_process() { return is_incognito_process_; }
@@ -49,6 +54,7 @@ class ChromeRenderProcessObserver : public RenderProcessObserver {
 
   static bool is_incognito_process_;
   scoped_ptr<ResourceDispatcherDelegate> resource_delegate_;
+  chrome::ChromeContentRendererClient* client_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeRenderProcessObserver);
 };

chrome/renderer/spellchecker/spellcheck.cc

@@ -36,18 +36,13 @@ bool SpellCheck::OnControlMessageReceived(const IPC::Message& message) {
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
 
-  if (message.type() == ViewMsg_PurgeMemory::ID) {
-    delete this;
-    new SpellCheck();
-  }
-
   return handled;
 }
 
 void SpellCheck::OnInit(IPC::PlatformFileForTransit bdict_file,
                         const std::vector<std::string>& custom_words,
                         const std::string& language,
-    bool auto_spell_correct) {
+                        bool auto_spell_correct) {
   Init(IPC::PlatformFileForTransitToPlatformFile(bdict_file),
        custom_words, language);
   auto_spell_correct_turned_on_ = auto_spell_correct;

chrome/renderer/spellchecker/spellcheck_provider.cc

@@ -202,3 +202,7 @@ void SpellCheckProvider::EnsureDocumentTag() {
   }
 #endif
 }
+
+void SpellCheckProvider::SetSpellCheck(SpellCheck* spellcheck) {
+  spellcheck_ = spellcheck;
+}

chrome/renderer/spellchecker/spellcheck_provider.h

@@ -53,6 +53,8 @@ class SpellCheckProvider : public RenderViewObserver,
   virtual bool OnMessageReceived(const IPC::Message& message);
   virtual void FocusedNodeChanged(const WebKit::WebNode& node);
 
+  void SetSpellCheck(SpellCheck* spellcheck);
+
  private:
   // WebKit::WebSpellCheckClient implementation.
   virtual void spellCheck(