Bug 1357287 - [1.1] Add multiprocess GeckoView setting. r=snorp

mobile/android/chrome/geckoview/geckoview.xul

@@ -10,7 +10,7 @@
         windowtype="navigator:browser"
         xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
 
-  <browser id="content" type="content" primary="true" src="about:blank" flex="1" remote="true"/>
+  <browser id="content" type="content" primary="true" src="about:blank" flex="1"/>
 
   <script type="application/javascript" src="chrome://geckoview/content/geckoview.js"/>
 </window>

mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoViewSettings.java

@@ -22,10 +22,23 @@ public final class GeckoViewSettings {
         }
     }
 
+    /*
+     * Key to enabled and disable tracking protection.
+     */
     public static final Key<Boolean> USE_TRACKING_PROTECTION =
         new Key<Boolean>("useTrackingProtection");
+    /*
+     * Key to enabled and disable private mode browsing.
+     */
     public static final Key<Boolean> USE_PRIVATE_MODE =
         new Key<Boolean>("usePrivateMode");
+    /*
+     * Key to enabled and disable multiprocess browsing (e10s).
+     * Note: can only be set during GeckoView initialization, changes during an
+     * active GeckoView session will be ignored.
+     */
+    public static final Key<Boolean> USE_MULTIPROCESS =
+        new Key<Boolean>("useMultiprocess");
 
     private final EventDispatcher mEventDispatcher;
     private final GeckoBundle mBundle;
@@ -40,6 +53,7 @@ public final class GeckoViewSettings {
 
         setBoolean(USE_TRACKING_PROTECTION, false);
         setBoolean(USE_PRIVATE_MODE, false);
+        setBoolean(USE_MULTIPROCESS, true);
     }
 
     /* package */ GeckoViewSettings(GeckoViewSettings settings, EventDispatcher eventDispatcher) {

mobile/android/modules/geckoview/GeckoViewSettings.jsm

@@ -23,10 +23,15 @@ function debug(aMsg) {
 
 // Handles GeckoView settings including:
 // * tracking protection
+// * multiprocess
 class GeckoViewSettings extends GeckoViewModule {
   init() {
     this._isSafeBrowsingInit = false;
     this._useTrackingProtection = false;
+
+    // We only allow to set this setting during initialization, further updates
+    // will be ignored.
+    this.useMultiprocess = !!this.settings.useMultiprocess;
   }
 
   onSettingsUpdate() {
@@ -52,4 +57,23 @@ class GeckoViewSettings extends GeckoViewModule {
       this._useTrackingProtection = aUse;
     }
   }
+
+  get useMultiprocess() {
+    return this.browser.getAttribute("remote") == "true";
+  }
+
+  set useMultiprocess(aUse) {
+    if (aUse == this.useMultiprocess) {
+      return;
+    }
+    let parentNode = this.browser.parentNode;
+    parentNode.removeChild(this.browser);
+
+    if (aUse) {
+      this.browser.setAttribute("remote", "true");
+    } else {
+      this.browser.removeAttribute("remote");
+    }
+    parentNode.appendChild(this.browser);
+  }
 }