Mac fullscreen low power: Add unittests

chrome/browser/ui/cocoa/browser_window_controller_private.mm

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "chrome/browser/ui/cocoa/browser_window_controller_private.h"
 
 #include <cmath>
 
 #import "base/auto_reset.h"
 #include "base/command_line.h"
@@ skipping 1177 matching lines @@
   exitingAppKitFullscreen_ = NO;
   isUsingCustomAnimation_ = NO;
 }
 
 - (NSArray*)customWindowsToEnterFullScreenForWindow:(NSWindow*)window {
   DCHECK([window isEqual:self.window]);
 
   if (![self shouldUseCustomAppKitFullscreenTransition:YES])
     return nil;
 
-  WebContents* webContents = [self webContents];
   NSWindow* lowPowerWindow = nil;
-  if (webContents) {
-    fullscreenLowPowerCoordinator_.reset(new FullscreenLowPowerCoordinatorCocoa(
-        [self window],
-        webContents->GetRenderWidgetHostView()->GetAcceleratedWidgetMac()));
-    lowPowerWindow =
-        fullscreenLowPowerCoordinator_->GetFullscreenLowPowerWindow();
+  static bool fullscreen_low_power_enabled_at_command_line =

[spqchan, 2016/06/08 21:43:58]

Why static? Do you mean const?

[ccameron, 2016/06/09 20:47:08]

Oh -- I wanted to avoid re-looking-up at each call. But it should be const, as
well -- added that.

+      base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableFullscreenLowPowerMode);
+  if (fullscreen_low_power_enabled_at_command_line) {
+    WebContents* webContents = [self webContents];
+    if (webContents && webContents->GetRenderWidgetHostView()) {
+      fullscreenLowPowerCoordinator_.reset(
+          new FullscreenLowPowerCoordinatorCocoa(
+              [self window], webContents->GetRenderWidgetHostView()
+                                 ->GetAcceleratedWidgetMac()));
+      lowPowerWindow =
+          fullscreenLowPowerCoordinator_->GetFullscreenLowPowerWindow();
+    }
   }
 
   fullscreenTransition_.reset(
       [[BrowserWindowFullscreenTransition alloc] initEnterWithController:self]);
 
   NSArray* customWindows =
       [fullscreenTransition_ customWindowsForFullScreenTransition];
   if (customWindows && lowPowerWindow)
     customWindows = [customWindows arrayByAddingObject:lowPowerWindow];
   else
@@ skipping 67 matching lines @@
   if (fullscreenLowPowerCoordinator_)
     fullscreenLowPowerCoordinator_->SetHasActiveSheet(false);
 }
 
 - (void)childWindowsDidChange {
   if (fullscreenLowPowerCoordinator_)
     fullscreenLowPowerCoordinator_->ChildWindowsChanged();
 }
 
 @end  // @implementation BrowserWindowController(Private)