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content/browser/renderer_host/render_widget_helper.cc

Index: content/browser/renderer_host/render_widget_helper.cc
diff --git a/content/browser/renderer_host/render_widget_helper.cc b/content/browser/renderer_host/render_widget_helper.cc
index 86395659010b08f94a70615f238ce6fe4bb60f9b..4e6d84e3a23fe5e3ce220805ccef051df68bb9fa 100644
--- a/content/browser/renderer_host/render_widget_helper.cc
+++ b/content/browser/renderer_host/render_widget_helper.cc
@@ -7,24 +7,32 @@
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/eintr_wrapper.h"
+#include "base/id_map.h"
+#include "base/lazy_instance.h"
 #include "base/threading/thread.h"
 #include "content/browser/gpu/gpu_surface_tracker.h"
 #include "content/browser/renderer_host/render_process_host_impl.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
 #include "content/browser/renderer_host/resource_dispatcher_host_impl.h"
 #include "content/common/view_messages.h"
-#include "content/public/browser/browser_thread.h"
 
 using content::BrowserThread;
 using content::RenderViewHostImpl;
 using content::ResourceDispatcherHostImpl;
 
-// A helper used with DidReceiveUpdateMsg that we hold a pointer to in
+namespace {
+
+base::LazyInstance<IDMap<RenderWidgetHelper> > g_widget_helpers =

[darin (slow to review), 2012/04/23 16:47:14]

it looks like you aren't using IDMap to create identifiers, so maybe this should
just be a std::map<int, RenderWidgetHelper>?  is it because IDMap uses
base::hash_map<...>?

[jbates, 2012/04/23 20:48:18]

You're right, I had copied another instance of a LazyInstance IDMap using
AddWithID, but in this case a std::map is a better fit (since IDMap says it's
optimal for storing close to one item). Done.

+    LAZY_INSTANCE_INITIALIZER;
+
+}  // namespace
+
+// A helper used with DidReceiveBackingStoreMsg that we hold a pointer to in
 // pending_paints_.
-class RenderWidgetHelper::UpdateMsgProxy {
+class RenderWidgetHelper::BackingStoreMsgProxy {
  public:
-  UpdateMsgProxy(RenderWidgetHelper* h, const IPC::Message& m);
-  ~UpdateMsgProxy();
+  BackingStoreMsgProxy(RenderWidgetHelper* h, const IPC::Message& m);
+  ~BackingStoreMsgProxy();
   void Run();
   void Cancel() { cancelled_ = true; }
 
@@ -35,26 +43,26 @@ class RenderWidgetHelper::UpdateMsgProxy {
   IPC::Message message_;
   bool cancelled_;  // If true, then the message will not be dispatched.
 
-  DISALLOW_COPY_AND_ASSIGN(UpdateMsgProxy);
+  DISALLOW_COPY_AND_ASSIGN(BackingStoreMsgProxy);
 };
 
-RenderWidgetHelper::UpdateMsgProxy::UpdateMsgProxy(
+RenderWidgetHelper::BackingStoreMsgProxy::BackingStoreMsgProxy(
     RenderWidgetHelper* h, const IPC::Message& m)
     : helper_(h),
       message_(m),
       cancelled_(false) {
 }
 
-RenderWidgetHelper::UpdateMsgProxy::~UpdateMsgProxy() {
+RenderWidgetHelper::BackingStoreMsgProxy::~BackingStoreMsgProxy() {
   // If the paint message was never dispatched, then we need to let the
   // helper know that we are going away.
   if (!cancelled_ && helper_)
-    helper_->OnDiscardUpdateMsg(this);
+    helper_->OnDiscardBackingStoreMsg(this);
 }
 
-void RenderWidgetHelper::UpdateMsgProxy::Run() {
+void RenderWidgetHelper::BackingStoreMsgProxy::Run() {
   if (!cancelled_) {
-    helper_->OnDispatchUpdateMsg(this);
+    helper_->OnDispatchBackingStoreMsg(this);
     helper_ = NULL;
   }
 }
@@ -70,6 +78,9 @@ RenderWidgetHelper::RenderWidgetHelper()
 }
 
 RenderWidgetHelper::~RenderWidgetHelper() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  g_widget_helpers.Get().Remove(render_process_id_);
+
   // The elements of pending_paints_ each hold an owning reference back to this
   // object, so we should not be destroyed unless pending_paints_ is empty!
   DCHECK(pending_paints_.empty());
@@ -84,12 +95,25 @@ void RenderWidgetHelper::Init(
     ResourceDispatcherHostImpl* resource_dispatcher_host) {
   render_process_id_ = render_process_id;
   resource_dispatcher_host_ = resource_dispatcher_host;
+
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      base::Bind(&IDMap<RenderWidgetHelper>::AddWithID,
+                 base::Unretained(g_widget_helpers.Pointer()),
+                 make_scoped_refptr(this), render_process_id_));
 }
 
 int RenderWidgetHelper::GetNextRoutingID() {
   return next_routing_id_.GetNext() + 1;
 }
 
+// static
+RenderWidgetHelper* RenderWidgetHelper::FromProcessHostID(
+    int render_process_host_id) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  return g_widget_helpers.Get().Lookup(render_process_host_id);
+}
+
 void RenderWidgetHelper::CancelResourceRequests(int render_widget_id) {
   if (render_process_id_ == -1)
     return;
@@ -110,19 +134,21 @@ void RenderWidgetHelper::SimulateSwapOutACK(
                  params));
 }
 
-bool RenderWidgetHelper::WaitForUpdateMsg(int render_widget_id,
-                                          const base::TimeDelta& max_delay,
-                                          IPC::Message* msg) {
+bool RenderWidgetHelper::WaitForBackingStoreMsg(
+    int render_widget_id,
+    const base::TimeDelta& max_delay,
+    IPC::Message* msg) {
   base::TimeTicks time_start = base::TimeTicks::Now();
 
   for (;;) {
-    UpdateMsgProxy* proxy = NULL;
+    BackingStoreMsgProxy* proxy = NULL;
     {
       base::AutoLock lock(pending_paints_lock_);
 
-      UpdateMsgProxyMap::iterator it = pending_paints_.find(render_widget_id);
+      BackingStoreMsgProxyMap::iterator it =
+          pending_paints_.find(render_widget_id);
       if (it != pending_paints_.end()) {
-        UpdateMsgProxyQueue &queue = it->second;
+        BackingStoreMsgProxyQueue &queue = it->second;
         DCHECK(!queue.empty());
         proxy = queue.front();
 
@@ -154,10 +180,10 @@ bool RenderWidgetHelper::WaitForUpdateMsg(int render_widget_id,
   return false;
 }
 
-void RenderWidgetHelper::DidReceiveUpdateMsg(const IPC::Message& msg) {
+void RenderWidgetHelper::DidReceiveBackingStoreMsg(const IPC::Message& msg) {
   int render_widget_id = msg.routing_id();
 
-  UpdateMsgProxy* proxy = new UpdateMsgProxy(this, msg);
+  BackingStoreMsgProxy* proxy = new BackingStoreMsgProxy(this, msg);
   {
     base::AutoLock lock(pending_paints_lock_);
 
@@ -170,19 +196,20 @@ void RenderWidgetHelper::DidReceiveUpdateMsg(const IPC::Message& msg) {
   event_.Signal();
 
   BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-                          base::Bind(&UpdateMsgProxy::Run, base::Owned(proxy)));
+      base::Bind(&BackingStoreMsgProxy::Run, base::Owned(proxy)));
 }
 
-void RenderWidgetHelper::OnDiscardUpdateMsg(UpdateMsgProxy* proxy) {
+void RenderWidgetHelper::OnDiscardBackingStoreMsg(BackingStoreMsgProxy* proxy) {
   const IPC::Message& msg = proxy->message();
 
   // Remove the proxy from the map now that we are going to handle it normally.
   {
     base::AutoLock lock(pending_paints_lock_);
 
-    UpdateMsgProxyMap::iterator it = pending_paints_.find(msg.routing_id());
+    BackingStoreMsgProxyMap::iterator it =
+        pending_paints_.find(msg.routing_id());
     DCHECK(it != pending_paints_.end());
-    UpdateMsgProxyQueue &queue = it->second;
+    BackingStoreMsgProxyQueue &queue = it->second;
     DCHECK(queue.front() == proxy);
 
     queue.pop_front();
@@ -191,8 +218,9 @@ void RenderWidgetHelper::OnDiscardUpdateMsg(UpdateMsgProxy* proxy) {
   }
 }
 
-void RenderWidgetHelper::OnDispatchUpdateMsg(UpdateMsgProxy* proxy) {
-  OnDiscardUpdateMsg(proxy);
+void RenderWidgetHelper::OnDispatchBackingStoreMsg(
+    BackingStoreMsgProxy* proxy) {
+  OnDiscardBackingStoreMsg(proxy);
 
   // It is reasonable for the host to no longer exist.
   content::RenderProcessHost* host =