[headless] Embed pak file into binary.

ui/base/resource/resource_bundle.cc

Index: ui/base/resource/resource_bundle.cc
diff --git a/ui/base/resource/resource_bundle.cc b/ui/base/resource/resource_bundle.cc
index 0f95c9e2e08dfdbeaa388cf67755dbdbc57ca9a6..bfd563382a4723ae198f81434daa234564252a1e 100644
--- a/ui/base/resource/resource_bundle.cc
+++ b/ui/base/resource/resource_bundle.cc
@@ -207,6 +207,14 @@ void ResourceBundle::InitSharedInstanceWithPakPath(const base::FilePath& path) {
 }
 
 // static
+void ResourceBundle::InitSharedInstanceWithPakBuffer(base::StringPiece buffer) {
+  InitSharedInstance(NULL);
+  g_shared_instance_->LoadTestResourcesFromBuffer(buffer, buffer);
+
+  g_shared_instance_->InitDefaultFontList();
+}
+
+// static
 void ResourceBundle::CleanupSharedInstance() {
   if (g_shared_instance_) {
     delete g_shared_instance_;
@@ -352,6 +360,25 @@ void ResourceBundle::LoadTestResources(const base::FilePath& path,
   }
 }
 
+void ResourceBundle::LoadTestResourcesFromBuffer(
+    base::StringPiece data,
+    base::StringPiece locale_data) {
+  is_test_resources_ = true;

[sadrul, 2016/05/17 15:07:50]

Add a comment why this is a test-resource?

[altimin, 2016/05/17 15:40:08]

Actually, I can use your advice here. Content shell uses
ResourceBundle::InitSharedInstanceWithPakPath, which calls
ResourceBuffer::LoadTestResources, which sets is_test_resources_ = true.

Since headless shell resembles content shell, we've used
InitSharedInstanceWithPakPath initially, and now switching to
InitSharedInstanceWithPakBuffer and LoadTestResourcesFromBuffer. 

If you have ideas how to make it better, I'd be glad to hear them.

[sadrul, 2016/05/19 18:28:26]

It looks like |is_test_resources_| is used to determine whether it's OK to fall
back to lower-res images. I feel like it would make sense to have an explicit
API on ResourceBundle to set that, instead of inferring this info based on what
function call was made to initialize the RB. But that's not an issue with this
CL.

If headless is OK with allowing fall-back to lower-res images, then this can be
set here. Please add a comment explaining that.

[altimin, 2016/05/19 19:23:30]

Done.

+  DCHECK(!ui::GetSupportedScaleFactors().empty());
+  const ScaleFactor scale_factor(ui::GetSupportedScaleFactors()[0]);
+  // Use the given resource pak for both common and localized resources.
+  std::unique_ptr<DataPack> data_pack(new DataPack(scale_factor));
+  if (data_pack->LoadFromBuffer(data))
+    AddDataPack(data_pack.release());
+
+  data_pack.reset(new DataPack(ui::SCALE_FACTOR_NONE));
+  if (data_pack->LoadFromBuffer(locale_data)) {
+    locale_resources_data_.reset(data_pack.release());
+  } else {
+    locale_resources_data_.reset(new DataPack(ui::SCALE_FACTOR_NONE));
+  }
+}
+
 void ResourceBundle::UnloadLocaleResources() {
   locale_resources_data_.reset();
 }