[Chromoting] Fix crash on initial connection (Mac).

remoting/host/video_frame_capturer_mac.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.
 
 #include "remoting/host/video_frame_capturer.h"
 
 #include <ApplicationServices/ApplicationServices.h>
 #include <Cocoa/Cocoa.h>
 #include <dlfcn.h>
 #include <IOKit/pwr_mgt/IOPMLib.h>
@@ skipping 639 matching lines @@
   // Release existing buffers, which will be of the wrong size.
   ReleaseBuffers();
   last_buffer_ = NULL;
 
   // Clear the dirty region, in case the display is down-sizing.
   helper_.ClearInvalidRegion();
 
   // Fetch the list if active displays and calculate their bounds.
   CGDisplayCount display_count;
   CGError error = CGGetActiveDisplayList(0, NULL, &display_count);
   CHECK_EQ(error, CGDisplayNoErr);

[Wez, 2012/10/22 23:40:43]

Add a DLOG_IF() here that logs when |display_count| is zero.

 
   display_ids_.resize(display_count);
   error = CGGetActiveDisplayList(display_count, &display_ids_[0],
                                  &display_count);
   CHECK_EQ(error, CGDisplayNoErr);
   CHECK_EQ(display_count, display_ids_.size());
 
   desktop_bounds_ = SkIRect::MakeEmpty();
   for (unsigned int d = 0; d < display_count; ++d) {
     CGRect display_bounds = CGDisplayBounds(display_ids_[d]);

[Wez, 2012/10/22 23:40:43]

Add a DLOG_IF() here that logs if |display_bounds.isEmpty()|.

     desktop_bounds_.join(CGRectToSkIRect(display_bounds));
   }
 
   // Re-mark the entire desktop as dirty.
   helper_.InvalidateScreen(SkISize::Make(desktop_bounds_.width(),
                                          desktop_bounds_.height()));
 
   // CgBlitPostLion uses CGDisplayCreateImage() to snapshot each display's
   // contents. Although the API exists in OS 10.6, it crashes the caller if
   // the machine has no monitor connected, so we fall back to depcreated APIs
@@ skipping 59 matching lines @@
   (*cgl_set_full_screen_)(cgl_context_);
   CGLSetCurrentContext(cgl_context_);
 
   size_t buffer_size = desktop_bounds_.width() * desktop_bounds_.height() *
                        sizeof(uint32_t);
   pixel_buffer_object_.Init(cgl_context_, buffer_size);
 }
 
 void VideoFrameCapturerMac::ScreenRefresh(CGRectCount count,
                                           const CGRect* rect_array) {
+  DCHECK(!desktop_bounds_.isEmpty());
   SkIRect skirect_array[count];
   for (CGRectCount i = 0; i < count; ++i) {
     skirect_array[i] = CGRectToSkIRect(rect_array[i]);
     skirect_array[i].offset(-desktop_bounds_.left(), -desktop_bounds_.top());
   }
   SkRegion region;
   region.setRects(skirect_array, count);
   InvalidateRegion(region);
 }
 
@@ skipping 29 matching lines @@
       display_configuration_capture_event_.Signal();
     }
   }
 }
 
 void VideoFrameCapturerMac::ScreenRefreshCallback(CGRectCount count,
                                                   const CGRect* rect_array,
                                                   void* user_parameter) {
   VideoFrameCapturerMac* capturer = reinterpret_cast<VideoFrameCapturerMac*>(
       user_parameter);
+  if (capturer->desktop_bounds_.isEmpty()) {
+    capturer->ScreenConfigurationChanged();
+  }

[Jamie, 2012/10/22 21:14:25]

ScreenConfigurationChanged is supposed to be called in response to the
DisplaysReconfigured notification indicating that reconfiguration is complete.
The fact that the desktop bounds are invalid suggests to me that this callback
is still pending, and calling ScreenConfigurationChanged explicitly is racy at
best. A better approach might be simply this callback to ignore on the
assumption that we'll get the DisplaysReconfigured notification soon and proceed
normally from that point.

   capturer->ScreenRefresh(count, rect_array);
 }
 
 void VideoFrameCapturerMac::ScreenUpdateMoveCallback(
     CGScreenUpdateMoveDelta delta,
     size_t count,
     const CGRect* rect_array,
     void* user_parameter) {
   VideoFrameCapturerMac* capturer = reinterpret_cast<VideoFrameCapturerMac*>(
       user_parameter);
@@ skipping 15 matching lines @@
 VideoFrameCapturer* VideoFrameCapturer::Create() {
   VideoFrameCapturerMac* capturer = new VideoFrameCapturerMac();
   if (!capturer->Init()) {
     delete capturer;
     capturer = NULL;
   }
   return capturer;
 }
 
 }  // namespace remoting