Bug 1061864 - Part 1: Add a prerendered flag to nsIDocShell; r=smaug

docshell/base/nsDocShell.cpp

@@ -838,6 +838,7 @@ nsDocShell::nsDocShell():
     mAllowKeywordFixup(false),
     mIsOffScreenBrowser(false),
     mIsActive(true),
+    mIsPrerendered(false),
     mIsAppTab(false),
     mUseGlobalHistory(false),
     mInPrivateBrowsing(false),
@@ -3386,6 +3387,11 @@ nsDocShell::SetDocLoaderParent(nsDocLoader * aParent)
         {
             SetIsActive(value);
         }
+        if (NS_SUCCEEDED(parentAsDocShell->GetIsPrerendered(&value))) {
+            if (value) {
+                SetIsPrerendered(true);
+            }
+        }
         if (NS_FAILED(parentAsDocShell->GetAllowDNSPrefetch(&value))) {
             value = false;
         }
@@ -6052,6 +6058,22 @@ nsDocShell::GetIsActive(bool *aIsActive)
     return NS_OK;
 }
 
+NS_IMETHODIMP
+nsDocShell::SetIsPrerendered(bool aPrerendered)
+{
+    MOZ_ASSERT(!aPrerendered || !mIsPrerendered,
+               "SetIsPrerendered(true) called on already prerendered docshell");
+    mIsPrerendered = aPrerendered;
+    return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDocShell::GetIsPrerendered(bool *aIsPrerendered)
+{
+    *aIsPrerendered = mIsPrerendered;
+    return NS_OK;
+}
+
 NS_IMETHODIMP
 nsDocShell::SetIsAppTab(bool aIsAppTab)
 {
@@ -8553,8 +8575,8 @@ nsDocShell::RestoreFromHistory()
 
         // this.AddChild(child) calls child.SetDocLoaderParent(this), meaning
         // that the child inherits our state. Among other things, this means
-        // that the child inherits our mIsActive and mInPrivateBrowsing, which
-        // is what we want.
+        // that the child inherits our mIsActive, mIsPrerendered and mInPrivateBrowsing,
+        // which is what we want.
         AddChild(childItem);
 
         childShell->SetAllowPlugins(allowPlugins);

docshell/base/nsDocShell.h

@@ -877,6 +877,7 @@ protected:
     bool                       mAllowKeywordFixup;
     bool                       mIsOffScreenBrowser;
     bool                       mIsActive;
+    bool                       mIsPrerendered;
     bool                       mIsAppTab;
     bool                       mUseGlobalHistory;
     bool                       mInPrivateBrowsing;

docshell/base/nsIDocShell.idl

@@ -54,7 +54,7 @@ interface nsITabParent;
  
 typedef unsigned long nsLoadFlags;
 
-[scriptable, builtinclass, uuid(c2756385-bc54-417b-9ae4-c5a40053a2a3)]
+[scriptable, builtinclass, uuid(fef3bae1-6673-4c49-9f5a-fcc075926730)]
 interface nsIDocShell : nsIDocShellTreeItem
 {
   /**
@@ -619,6 +619,13 @@ interface nsIDocShell : nsIDocShellTreeItem
    */
   attribute boolean isActive;
 
+  /**
+   * Puts the docshell in prerendering mode. noscript because we want only
+   * native code to be able to put a docshell in prerendering.
+   */
+  [noscript] void SetIsPrerendered(in boolean prerendered);
+  readonly attribute boolean isPrerendered;
+
   /**
    * The ID of the docshell in the session history.
    */