Bug 1334642 - Cache luminance values for each toolbar in ToolbarIconColor. r=dao,mconley

* Track window states: active, fullscreen and tabsintitlebar for each window
* Use toolbar.id and window state to store and retrieve values from cache
* Note: As each window has its own ToolbarIconColor object, the cache is not currently shared across windows
* inferFromText callers pass in a reason and associated value, which is used to update the state we track, and potentially clear out the cache
* Create new windows test directory for browser-window-specific tests like this
* Test for the ToolbarIconColor changes to avoid sync style flushes when windows activate/deactivate
* Skip test for windows 8, follow-up filed as bug 1356684

MozReview-Commit-ID: JDJ3RtL4Lge

browser/base/content/browser-fullScreenAndPointerLock.js

@@ -636,7 +636,8 @@ var FullScreen = {
       }
     }
 
-    ToolbarIconColor.inferFromText();
+    ToolbarIconColor.inferFromText("fullscreen", aEnterFS);
+
 
     // For Lion fullscreen, all fullscreen controls are hidden, don't
     // bother to touch them. If we don't stop here, the following code

browser/base/content/browser-tabsintitlebar.js

@@ -247,7 +247,8 @@ var TabsInTitlebar = {
       menubar.style.paddingBottom = "";
     }
 
-    ToolbarIconColor.inferFromText();
+    ToolbarIconColor.inferFromText("tabsintitlebar", TabsInTitlebar.enabled);
+
     if (CustomizationHandler.isCustomizing()) {
       gCustomizeMode.updateLWTStyling();
     }

browser/base/content/test/windows/.eslintrc.js

@@ -0,0 +1,7 @@
+"use strict";
+
+module.exports = {
+  "extends": [
+    "plugin:mozilla/browser-test"
+  ]
+};

browser/base/content/test/windows/browser.ini

@@ -0,0 +1,2 @@
+[DEFAULT]
+[browser_toolbariconcolor_restyles.js]

browser/base/content/test/windows/browser_toolbariconcolor_restyles.js

@@ -0,0 +1,44 @@
+"use strict";
+
+/**
+ * Ensure redundant style flushes are not triggered when switching between windows
+ */
+add_task(function* test_toolbar_element_restyles_on_activation() {
+  if (AppConstants.platform != "win" && AppConstants.version == 8) {
+    ok(true, "Skipping this test for windows 8");
+    return;
+  }
+
+  let restyles = {
+    win1:  {},
+    win2:  {}
+  };
+
+  // create a window and snapshot the elementsStyled
+  let win1 = yield BrowserTestUtils.openNewBrowserWindow();
+  let utils1 = SpecialPowers.getDOMWindowUtils(win1);
+  restyles.win1.initial = utils1.elementsRestyled;
+
+  // create a 2nd window and snapshot the elementsStyled
+  let win2 = yield BrowserTestUtils.openNewBrowserWindow();
+  let utils2 = SpecialPowers.getDOMWindowUtils(win2);
+  restyles.win2.initial = utils2.elementsRestyled;
+
+  // switch back to 1st window, and snapshot elementsStyled
+  win1.focus();
+  restyles.win1.activate = utils1.elementsRestyled;
+  restyles.win2.deactivate = utils2.elementsRestyled;
+
+  // switch back to 2nd window, and snapshot elementsStyled
+  win2.focus();
+  restyles.win2.activate = utils2.elementsRestyled;
+  restyles.win1.deactivate = utils1.elementsRestyled;
+
+  is(restyles.win1.activate - restyles.win1.deactivate, 0,
+      "No elements restyled when re-activating/deactivating a window");
+  is(restyles.win2.activate - restyles.win2.deactivate, 0,
+      "No elements restyled when re-activating/deactivating a window");
+
+  yield BrowserTestUtils.closeWindow(win1);
+  yield BrowserTestUtils.closeWindow(win2);
+});

browser/base/moz.build

@@ -35,6 +35,7 @@ BROWSER_CHROME_MANIFESTS += [
     'content/test/urlbar/browser.ini',
     'content/test/webextensions/browser.ini',
     'content/test/webrtc/browser.ini',
+    'content/test/windows/browser.ini',
 ]
 
 if CONFIG['MOZ_UPDATER']: