[EoS] Add scale factor header to catalog request.

This adds the scale factor of the android device into a new header
called "X-Device-Scale-Factor". The scale factor is derived from
android.util.DisplayMetrics.density.

Change-Id: Ia8f26435fdc780354e753f87632aca03811c144a

Bug: 893238
Change-Id: Ia8f26435fdc780354e753f87632aca03811c144a
Reviewed-on: https://chromium-review.googlesource.com/c/1260208
Commit-Queue: Peter Williamson <petewil@chromium.org>
Reviewed-by: Justin DeWitt <dewittj@chromium.org>
Cr-Commit-Position: refs/heads/master@{#597636}

chrome/android/java/src/org/chromium/chrome/browser/explore_sites/ExploreSitesBridge.java

@@ -4,9 +4,13 @@
 
 package org.chromium.chrome.browser.explore_sites;
 
+import android.content.Context;
 import android.graphics.Bitmap;
+import android.util.DisplayMetrics;
+import android.view.WindowManager;
 
 import org.chromium.base.Callback;
+import org.chromium.base.ContextUtils;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.JNINamespace;
 import org.chromium.chrome.browser.profiles.Profile;
@@ -65,6 +69,21 @@ public class ExploreSitesBridge {
         ExploreSitesBackgroundTask.schedule(false /* updateCurrent */);
     }
 
+    /**
+     * Returns the scale factor on this device.
+     */
+    @CalledByNative
+    static float getScaleFactorFromDevice() {
+        // Get DeviceMetrics from context.
+        DisplayMetrics metrics = new DisplayMetrics();
+        ((WindowManager) ContextUtils.getApplicationContext().getSystemService(
+                 Context.WINDOW_SERVICE))
+                .getDefaultDisplay()
+                .getMetrics(metrics);
+        // Get density and return it.
+        return metrics.density;
+    }
+
     static native int nativeGetVariation();
     private static native void nativeGetEspCatalog(Profile profile,
             List<ExploreSitesCategory> result, Callback<List<ExploreSitesCategory>> callback);

chrome/browser/android/explore_sites/explore_sites_bridge.cc

@@ -175,4 +175,10 @@ void ExploreSitesBridge::ScheduleDailyTask() {
   Java_ExploreSitesBridge_scheduleDailyTask(env);
 }
 
+float ExploreSitesBridge::GetScaleFactorFromDevice() {
+  JNIEnv* env = base::android::AttachCurrentThread();
+  // Get scale factor from Java as a float.
+  return Java_ExploreSitesBridge_getScaleFactorFromDevice(env);
+}
+
 }  // namespace explore_sites

chrome/browser/android/explore_sites/explore_sites_bridge.h

@@ -14,6 +14,9 @@ class ExploreSitesBridge {
   // The catalog update task checks that the feature is enabled and if not,
   // unschedules itself.
   static void ScheduleDailyTask();
+
+  // Gets the device screen scale factor from Android.
+  static float GetScaleFactorFromDevice();
 };
 
 }  // namespace explore_sites

chrome/browser/android/explore_sites/explore_sites_fetcher.cc

@@ -16,6 +16,7 @@
 #include "base/version.h"
 #include "chrome/browser/android/chrome_feature_list.h"
 #include "chrome/browser/android/explore_sites/catalog.pb.h"
+#include "chrome/browser/android/explore_sites/explore_sites_bridge.h"
 #include "chrome/browser/android/explore_sites/explore_sites_feature.h"
 #include "chrome/browser/android/explore_sites/explore_sites_types.h"
 #include "chrome/browser/android/explore_sites/url_util.h"
@@ -153,6 +154,7 @@ ExploreSitesFetcher::ExploreSitesFetcher(
       max_failure_count_(is_immediate_fetch
                              ? kMaxFailureCountForImmediateFetch
                              : kMaxFailureCountForBackgroundFetch),
+      device_delegate_(std::make_unique<DeviceDelegate>()),
       callback_(std::move(callback)),
       url_loader_factory_(loader_factory),
       weak_factory_(this) {
@@ -183,6 +185,10 @@ void ExploreSitesFetcher::Start() {
   resource_request->headers.SetHeader("X-Client-Version", client_version_);
   resource_request->headers.SetHeader(net::HttpRequestHeaders::kContentType,
                                       kRequestContentType);
+  std::string scale_factor =
+      std::to_string(device_delegate_->GetScaleFactorFromDevice());
+  resource_request->headers.SetHeader("X-Device-Scale-Factor", scale_factor);
+
   if (!accept_languages_.empty()) {
     resource_request->headers.SetHeader(
         net::HttpRequestHeaders::kAcceptLanguage, accept_languages_);
@@ -204,6 +210,15 @@ void ExploreSitesFetcher::Start() {
                      weak_factory_.GetWeakPtr()));
 }
 
+float ExploreSitesFetcher::DeviceDelegate::GetScaleFactorFromDevice() {
+  return ExploreSitesBridge::GetScaleFactorFromDevice();
+}
+
+void ExploreSitesFetcher::SetDeviceDelegateForTest(
+    std::unique_ptr<ExploreSitesFetcher::DeviceDelegate> device_delegate) {
+  device_delegate_ = std::move(device_delegate);
+}
+
 void ExploreSitesFetcher::OnSimpleLoaderComplete(
     std::unique_ptr<std::string> response_body) {
   ExploreSitesRequestStatus status = HandleResponseCode();

chrome/browser/android/explore_sites/explore_sites_fetcher.h

@@ -57,6 +57,18 @@ class ExploreSitesFetcher {
 
   void disable_retry_for_testing() { disable_retry_for_testing_ = true; }
 
+  // Delegate that knows how to get data from the device.  Can be overridden for
+  // testing.
+  class DeviceDelegate {
+   public:
+    DeviceDelegate() = default;
+    virtual ~DeviceDelegate() = default;
+    virtual float GetScaleFactorFromDevice();
+  };
+
+  // Allow overriding device specific functionality for testing
+  void SetDeviceDelegateForTest(std::unique_ptr<DeviceDelegate> delegate);
+
  private:
   explicit ExploreSitesFetcher(
       bool is_immediate_fetch,
@@ -81,6 +93,7 @@ class ExploreSitesFetcher {
   int max_failure_count_;
   bool disable_retry_for_testing_ = false;
 
+  std::unique_ptr<DeviceDelegate> device_delegate_;
   Callback callback_;
 
   scoped_refptr<network::SharedURLLoaderFactory> url_loader_factory_;

chrome/browser/android/explore_sites/explore_sites_fetcher_unittest.cc

@@ -41,6 +41,12 @@ const char kTestData[] = "Any data.";
 
 namespace explore_sites {
 
+class TestingDeviceDelegate : public ExploreSitesFetcher::DeviceDelegate {
+ public:
+  TestingDeviceDelegate() = default;
+  float GetScaleFactorFromDevice() override { return 1.5; }
+};
+
 // TODO(freedjm): Add tests for the headers.
 class ExploreSitesFetcherTest : public testing::Test {
  public:
@@ -249,6 +255,7 @@ std::unique_ptr<ExploreSitesFetcher> ExploreSitesFetcherTest::CreateFetcher(
           test_shared_url_loader_factory_, StoreResult());
   if (disable_retry)
     fetcher->disable_retry_for_testing();
+  fetcher->SetDeviceDelegateForTest(std::make_unique<TestingDeviceDelegate>());
   fetcher->Start();
   return fetcher;
 }
@@ -328,6 +335,7 @@ TEST_F(ExploreSitesFetcherTest, TestHeaders) {
   net::HttpRequestHeaders headers = last_resource_request.headers;
   std::string content_type;
   std::string languages;
+  std::string scale_factor;
   bool success;
 
   success = headers.HasHeader("x-goog-api-key");
@@ -336,15 +344,19 @@ TEST_F(ExploreSitesFetcherTest, TestHeaders) {
   success = headers.HasHeader("X-Client-Version");
   EXPECT_TRUE(success);
 
+  success = headers.GetHeader("X-Device-Scale-Factor", &scale_factor);
+  EXPECT_TRUE(success);
+  EXPECT_EQ(1.5, std::stof(scale_factor));
+
   success =
       headers.GetHeader(net::HttpRequestHeaders::kContentType, &content_type);
   EXPECT_TRUE(success);
-  EXPECT_EQ(content_type, "application/x-protobuf");
+  EXPECT_EQ("application/x-protobuf", content_type);
 
   success =
       headers.GetHeader(net::HttpRequestHeaders::kAcceptLanguage, &languages);
   EXPECT_TRUE(success);
-  EXPECT_EQ(languages, kAcceptLanguages);
+  EXPECT_EQ(kAcceptLanguages, languages);
 
   // The finch header should not be set since the experiment is not on.
   success = headers.HasHeader("X-Google-Chrome-Experiment-Tag");