Bug 343515 - need API for tabbrowsers to tell docshells they're visible/hidden.r=gavin,sr=bz,a=blocker

docshell/base/nsDocShell.cpp

@@ -703,6 +703,7 @@ nsDocShell::nsDocShell():
     mAllowAuth(PR_TRUE),
     mAllowKeywordFixup(PR_FALSE),
     mIsOffScreenBrowser(PR_FALSE),
+    mIsActive(PR_TRUE),
     mFiredUnloadEvent(PR_FALSE),
     mEODForCurrentDocument(PR_FALSE),
     mURIResultedInDocument(PR_FALSE),
@@ -2496,6 +2497,10 @@ nsDocShell::SetDocLoaderParent(nsDocLoader * aParent)
         {
             SetAllowImages(value);
         }
+        if (NS_SUCCEEDED(parentAsDocShell->GetIsActive(&value)))
+        {
+            SetIsActive(value);
+        }
         if (NS_FAILED(parentAsDocShell->GetAllowDNSPrefetch(&value))) {
             value = PR_FALSE;
         }
@@ -4618,6 +4623,40 @@ nsDocShell::GetIsOffScreenBrowser(PRBool *aIsOffScreen)
     return NS_OK;
 }
 
+NS_IMETHODIMP
+nsDocShell::SetIsActive(PRBool aIsActive)
+{
+  // We disallow setting active on chrome docshells.
+  if (mItemType == nsIDocShellTreeItem::typeChrome)
+    return NS_ERROR_INVALID_ARG;
+
+  // Keep track ourselves.
+  mIsActive = aIsActive;
+
+  // Tell the PresShell about it.
+  nsCOMPtr<nsIPresShell> pshell;
+  GetPresShell(getter_AddRefs(pshell));
+  if (pshell)
+    pshell->SetIsActive(aIsActive);
+
+  // Recursively tell all of our children
+  PRInt32 n = mChildList.Count();
+  for (PRInt32 i = 0; i < n; ++i) {
+      nsCOMPtr<nsIDocShell> docshell = do_QueryInterface(ChildAt(i));
+      if (docshell)
+        docshell->SetIsActive(aIsActive);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDocShell::GetIsActive(PRBool *aIsActive)
+{
+  *aIsActive = mIsActive;
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsDocShell::SetVisibility(PRBool aVisibility)
 {
@@ -6909,7 +6948,10 @@ nsDocShell::RestoreFromHistory()
 
         PRBool allowDNSPrefetch;
         childShell->GetAllowDNSPrefetch(&allowDNSPrefetch);
-        
+
+        // 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, which is what we want.
         AddChild(childItem);
 
         childShell->SetAllowPlugins(allowPlugins);