Send correct DPI to client.

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 100 matching lines @@
     cgl_context_ = NULL;
     pixel_buffer_object_ = 0;
   }
 }
 
 // A class representing a full-frame pixel buffer.
 class VideoFrameBuffer {
  public:
   VideoFrameBuffer() :
       size_(SkISize::Make(0, 0)),
+      dpi_(SkIPoint::Make(0, 0)),
       bytes_per_row_(0),
       needs_update_(true) {
   }
 
   // If the buffer is marked as needing to be updated (for example after the
   // screen mode changes) and is the wrong size, then release the old buffer
   // and create a new one.
   void Update() {
     if (needs_update_) {
       needs_update_ = false;
       CGDirectDisplayID mainDevice = CGMainDisplayID();
       int width = CGDisplayPixelsWide(mainDevice);
       int height = CGDisplayPixelsHigh(mainDevice);

[Jamie, 2012/07/26 00:57:17]

We could get width and height from deviceDescription as well. I'm not sure if
that change makes sense, since what we have has been working fine.

[Lambros, 2012/07/26 01:21:59]

Well, I suppose you could use CGDisplayScreenSize() to get the physical size in
mm, and then do the arithmetic to derive the DPI.  Seems a bit silly though :)

       if (width != size_.width() || height != size_.height()) {
         size_.set(width, height);
         bytes_per_row_ = width * sizeof(uint32_t);
         size_t buffer_size = width * height * sizeof(uint32_t);
         ptr_.reset(new uint8[buffer_size]);
       }
+      NSScreen* screen = [NSScreen mainScreen];
+      NSDictionary* attr = [screen deviceDescription];
+      NSSize resolution = [[attr objectForKey: NSDeviceResolution] sizeValue];

[Lambros, 2012/07/26 01:21:59]

nit: no space after colon

+      dpi_.set(resolution.width, resolution.height);
     }
   }
 
   SkISize size() const { return size_; }
+  SkIPoint dpi() const { return dpi_; }
   int bytes_per_row() const { return bytes_per_row_; }
   uint8* ptr() const { return ptr_.get(); }
 
   void set_needs_update() { needs_update_ = true; }
 
  private:
   SkISize size_;
+  SkIPoint dpi_;
   int bytes_per_row_;
   scoped_array<uint8> ptr_;
   bool needs_update_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoFrameBuffer);
 };
 
 // A class to perform video frame capturing for mac.
 class VideoFrameCapturerMac : public VideoFrameCapturer {
  public:
@@ skipping 224 matching lines @@
   DataPlanes planes;
   planes.data[0] = current_buffer.ptr();
   planes.strides[0] = current_buffer.bytes_per_row();
   if (flip) {
     planes.strides[0] = -planes.strides[0];
     planes.data[0] +=
         (current_buffer.size().height() - 1) * current_buffer.bytes_per_row();
   }
 
   data = new CaptureData(planes, current_buffer.size(), pixel_format());
+  data->set_dpi(current_buffer.dpi());
   data->mutable_dirty_region() = region;
 
   current_buffer_ = (current_buffer_ + 1) % kNumBuffers;
   helper_.set_size_most_recent(data->size());
   display_configuration_capture_event_.Signal();
 
   CaptureCursor();
 
   callback.Run(data);
 }
@@ skipping 361 matching lines @@
 VideoFrameCapturer* VideoFrameCapturer::Create() {
   VideoFrameCapturerMac* capturer = new VideoFrameCapturerMac();
   if (!capturer->Init()) {
     delete capturer;
     capturer = NULL;
   }
   return capturer;
 }
 
 }  // namespace remoting