Check that ChromeV8Contexts are valid before running ChromeV8ContextSet::ForEach

for them. This patch pre-empts likely breakage caused by r204157.

BUG=none
TBR=koz@chromium.org

Review URL: https://codereview.chromium.org/16469002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@204403 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 15 insertions, 9 deletions

diff --git a/chrome/renderer/extensions/chrome_v8_context.cc b/chrome/renderer/extensions/chrome_v8_context.cc
index c95a420..9cae7e7 100644
--- a/chrome/renderer/extensions/chrome_v8_context.cc
+++ b/chrome/renderer/extensions/chrome_v8_context.cc
@@ -151,8 +151,4 @@ void ChromeV8Context::OnResponseReceived(const std::string& name,
   }
 }
 
-bool ChromeV8Context::is_valid() const {
-  return !v8_context_.get().IsEmpty();
-}
-
 }  // namespace extensions
diff --git a/chrome/renderer/extensions/chrome_v8_context.h b/chrome/renderer/extensions/chrome_v8_context.h
index 55b8d59..5c7bfd8 100644
--- a/chrome/renderer/extensions/chrome_v8_context.h
+++ b/chrome/renderer/extensions/chrome_v8_context.h
@@ -39,6 +39,12 @@ class ChromeV8Context : public RequestSender::Source {
   // ModuleSystem.
   void Invalidate();
 
+  // Returns true if this context is still valid, false if it isn't.
+  // A context becomes invalid via Invalidate().
+  bool is_valid() const {
+    return !v8_context_.get().IsEmpty();
+  }
+
   v8::Handle<v8::Context> v8_context() const {
     return v8_context_.get();
   }
@@ -100,8 +106,6 @@ class ChromeV8Context : public RequestSender::Source {
                                   const std::string& error) OVERRIDE;
 
  private:
-  bool is_valid() const;
-
   // The v8 context the bindings are accessible to.
   ScopedPersistent<v8::Context> v8_context_;
 
diff --git a/chrome/renderer/extensions/chrome_v8_context_set.cc b/chrome/renderer/extensions/chrome_v8_context_set.cc
index c79cd5c..12084ff 100644
--- a/chrome/renderer/extensions/chrome_v8_context_set.cc
+++ b/chrome/renderer/extensions/chrome_v8_context_set.cc
@@ -87,20 +87,26 @@ void ChromeV8ContextSet::ForEach(
 
   for (ContextSet::iterator it = contexts.begin(); it != contexts.end();
        ++it) {
+    ChromeV8Context* context = *it;
+
+    // For the same reason as above, contexts may become invalid while we run.
+    if (!context->is_valid())
+      continue;
+
     if (!extension_id.empty()) {
-      const Extension* extension = (*it)->extension();
+      const Extension* extension = context->extension();
       if (!extension || (extension_id != extension->id()))
         continue;
     }
 
-    content::RenderView* context_render_view = (*it)->GetRenderView();
+    content::RenderView* context_render_view = context->GetRenderView();
     if (!context_render_view)
       continue;
 
     if (render_view && render_view != context_render_view)
       continue;
 
-    callback.Run(*it);
+    callback.Run(context);
   }
 }