Bug 755001 - Allow <iframe mozbrowser> to be explicitly in- or out-of-process. r=smaug

b2g/app/b2g.js

@@ -425,10 +425,12 @@ pref("browser.link.open_newwindow", 3);
 // 2: don't divert window.open with features
 pref("browser.link.open_newwindow.restriction", 0);
 
-// Enable browser frames, but not OOP.
+// Enable browser frames (including OOP), but make in-process browser frames
+// the default.
 pref("dom.mozBrowserFramesEnabled", true);
 pref("dom.mozBrowserFramesWhitelist", "http://homescreen.gaiamobile.org,http://browser.gaiamobile.org");
-pref("dom.ipc.tabs.disabled", true);
+pref("dom.ipc.tabs.disabled", false);
+pref("dom.ipc.browser_frames.oop_by_default", false);
 
 // Temporary permission hack for WebSMS
 pref("dom.sms.enabled", true);

content/base/src/nsFrameLoader.cpp

@@ -1400,11 +1400,18 @@ nsFrameLoader::ShouldUseRemoteProcess()
     return false;
   }
 
-  return OwnerIsBrowserFrame() ||
-         (bool) mOwnerContent->AttrValueIs(kNameSpaceID_None,
-                                           nsGkAtoms::Remote,
-                                           nsGkAtoms::_true,
-                                           eCaseMatters);
+  // If we're an <iframe mozbrowser> and we don't have a "remote" attribute,
+  // fall back to the default.
+  if (OwnerIsBrowserFrame() &&
+      !mOwnerContent->HasAttr(kNameSpaceID_None, nsGkAtoms::Remote)) {
+
+    return Preferences::GetBool("dom.ipc.browser_frames.oop_by_default", false);
+  }
+
+  return mOwnerContent->AttrValueIs(kNameSpaceID_None,
+                                    nsGkAtoms::Remote,
+                                    nsGkAtoms::_true,
+                                    eCaseMatters);
 }
 
 nsresult