[Chromecast] Handle device scale factor correctly

chromecast/browser/cast_content_browser_client.cc

 // Copyright 2014 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 "chromecast/browser/cast_content_browser_client.h"
 
 #include <stddef.h>
 
 #include <string>
 #include <utility>
 
 #include "base/base_switches.h"
 #include "base/command_line.h"
 #include "base/files/scoped_file.h"
 #include "base/i18n/rtl.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/path_service.h"
 #include "base/strings/utf_string_conversions.h"
 #include "build/build_config.h"
 #include "chromecast/base/cast_constants.h"
 #include "chromecast/base/cast_paths.h"
 #include "chromecast/base/chromecast_switches.h"
 #include "chromecast/browser/cast_browser_context.h"
 #include "chromecast/browser/cast_browser_main_parts.h"
 #include "chromecast/browser/cast_browser_process.h"
 #include "chromecast/browser/cast_network_delegate.h"
 #include "chromecast/browser/cast_quota_permission_context.h"
 #include "chromecast/browser/cast_resource_dispatcher_host_delegate.h"
+#include "chromecast/browser/cast_web_contents_user_data.h"
 #include "chromecast/browser/geolocation/cast_access_token_store.h"
 #include "chromecast/browser/media/cma_message_filter_host.h"
 #include "chromecast/browser/service/cast_service_simple.h"
 #include "chromecast/browser/url_request_context_factory.h"
 #include "chromecast/common/global_descriptors.h"
 #include "chromecast/media/audio/cast_audio_manager.h"
 #include "chromecast/media/cma/backend/media_pipeline_backend_manager.h"
 #include "chromecast/public/media/media_pipeline_backend.h"
 #include "components/crash/content/app/breakpad_linux.h"
 #include "components/crash/content/browser/crash_handler_host_linux.h"
 #include "components/network_hints/browser/network_hints_message_filter.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/certificate_request_result_type.h"
 #include "content/public/browser/client_certificate_delegate.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/resource_dispatcher_host.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/common/content_descriptors.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/url_constants.h"
 #include "content/public/common/web_preferences.h"
 #include "net/ssl/ssl_cert_request_info.h"
 #include "net/url_request/url_request_context_getter.h"
+#include "ui/gfx/screen.h"
 #include "ui/gl/gl_switches.h"
 
 #if defined(ENABLE_MOJO_MEDIA_IN_BROWSER_PROCESS)
 #include "chromecast/browser/media/cast_mojo_media_client.h"
 #include "media/mojo/services/mojo_media_application.h"  // nogncheck
 #endif  // ENABLE_MOJO_MEDIA_IN_BROWSER_PROCESS
 
 #if defined(OS_ANDROID)
 #include "components/crash/content/browser/crash_dump_manager_android.h"
 #include "components/external_video_surface/browser/android/external_video_surface_container_impl.h"
@@ skipping 206 matching lines @@
   prefs->allow_scripts_to_close_windows = true;
   // TODO(lcwu): http://crbug.com/391089. This pref is set to true by default
   // because some content providers such as YouTube use plain http requests
   // to retrieve media data chunks while running in a https page. This pref
   // should be disabled once all the content providers are no longer doing that.
   prefs->allow_running_insecure_content = true;
 
   // Enable 5% margins for WebVTT cues to keep within title-safe area
   prefs->text_track_margin_percentage = 5;
 
+  // This block of logic allows us to force 720p resolution for apps which don't
+  // handle scaling to higher resolutions (i.e. were built assuming 720p and
+  // have layout or performance problems at anything else).
+  // We use the viewport tag approach and ViewportStyle::TELEVISION to force a
+  // 720p layout viewport in this case.
+  // TODO(halliwell): require apps to handle scaling to any resolution; then
+  // we can simply run at the platform's native resolution.
 #if defined(OS_ANDROID)
-  // Enable the television style for viewport so that all cast apps have a
-  // 1280px wide layout viewport by default.
+  // Android has viewport enabled by default.  Disable for consistency with
+  // Linux (only enable below for 720p app case).
   DCHECK(prefs->viewport_enabled);
   DCHECK(prefs->viewport_meta_enabled);
-  prefs->viewport_style = content::ViewportStyle::TELEVISION;
+  prefs->viewport_enabled = false;

[alokp, 2016/05/11 16:46:53]

This seems risky to me. I am not sure what else we might break by disabling
viewport on Android. You should ask blink folks for advice.

I was under the impression that we would attempt the opposite - enable viewport
on non-android platforms. That gives applications most freedom to either use the
default viewport or define their own.

+  prefs->viewport_meta_enabled = false;
 #endif  // defined(OS_ANDROID)
+
+  content::WebContents* web_contents =
+      content::WebContents::FromRenderViewHost(render_view_host);
+  if (web_contents) {
+    CastWebContentsUserData* user_data =
+        static_cast<CastWebContentsUserData*>(
+            web_contents->GetUserData(CastWebContentsUserData::UserDataKey()));
+    if (user_data->resolution_height() == 720) {
+      prefs->viewport_enabled = true;
+      prefs->viewport_meta_enabled = true;
+      prefs->viewport_style = content::ViewportStyle::TELEVISION;
+
+      gfx::Size display_size =
+          gfx::Screen::GetScreen()->GetPrimaryDisplay().size();
+      const float scale_factor = display_size.height() / 720.0f;
+      prefs->default_minimum_page_scale_factor = scale_factor;
+      prefs->default_maximum_page_scale_factor = scale_factor;
+    }
+  }
 }
 
 void CastContentBrowserClient::ResourceDispatcherHostCreated() {
   CastBrowserProcess::GetInstance()->SetResourceDispatcherHostDelegate(
       base::WrapUnique(new CastResourceDispatcherHostDelegate));
   content::ResourceDispatcherHost::Get()->SetDelegate(
       CastBrowserProcess::GetInstance()->resource_dispatcher_host_delegate());
 }
 
 std::string CastContentBrowserClient::GetApplicationLocale() {
@@ skipping 213 matching lines @@
         process_type, dumps_path, false /* upload */);
   // StartUploaderThread() even though upload is diferred.
   // Breakpad-related memory is freed in the uploader thread.
   crash_handler->StartUploaderThread();
   return crash_handler;
 }
 #endif  // !defined(OS_ANDROID)
 
 }  // namespace shell
 }  // namespace chromecast