Variations changes to support WebLayer clients.

WebLayer will be using VariationsService but it's distinct from android
chrome so we need a way to override the platform in the variations url
request.

Bug: 1025612
Change-Id: Ie4f9f6bfabc3a6b9234fcf5589ad9f5b98c3224f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1951012
Commit-Queue: Alex Clarke <alexclarke@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#736953}

components/variations/field_trial_config/field_trial_util_unittest.cc

@@ -157,7 +157,8 @@ TEST_F(FieldTrialUtilTest, AssociateParamsFromFieldTrialConfig) {
 TEST_F(FieldTrialUtilTest,
        AssociateParamsFromFieldTrialConfigWithEachPlatform) {
   const Study::Platform all_platforms[] = {
-      Study::PLATFORM_ANDROID,
+      Study::PLATFORM_ANDROID,  // Comment to prevent clang format bin packing.
+      Study::PLATFORM_ANDROID_WEBLAYER,
       Study::PLATFORM_ANDROID_WEBVIEW,
       Study::PLATFORM_CHROMEOS,
       Study::PLATFORM_FUCHSIA,

components/variations/proto/study.proto

@@ -183,14 +183,15 @@ message Study {
   // Possible Chrome operating system platforms.
   // These names must match those in tools/variations/fieldtrial_to_struct.py.
   enum Platform {
-    PLATFORM_WINDOWS         = 0;
-    PLATFORM_MAC             = 1;
-    PLATFORM_LINUX           = 2;
-    PLATFORM_CHROMEOS        = 3;
-    PLATFORM_ANDROID         = 4;
-    PLATFORM_IOS             = 5;
+    PLATFORM_WINDOWS = 0;
+    PLATFORM_MAC = 1;
+    PLATFORM_LINUX = 2;
+    PLATFORM_CHROMEOS = 3;
+    PLATFORM_ANDROID = 4;
+    PLATFORM_IOS = 5;
     PLATFORM_ANDROID_WEBVIEW = 6;
-    PLATFORM_FUCHSIA         = 7;
+    PLATFORM_FUCHSIA = 7;
+    PLATFORM_ANDROID_WEBLAYER = 8;
   }
 
   // Possible form factors Chrome is running on.

components/variations/service/variations_service.cc

@@ -399,8 +399,10 @@ GURL VariationsService::GetVariationsServerURL(HttpOptions http_options) {
     server_url = net::AppendOrReplaceQueryParameter(server_url, "restrict",
                                                     restrict_mode);
   }
-  server_url = net::AppendOrReplaceQueryParameter(server_url, "osname",
-                                                  GetPlatformString());
+  server_url = net::AppendOrReplaceQueryParameter(
+      server_url, "osname",
+      osname_server_param_override_.empty() ? GetPlatformString()
+                                            : osname_server_param_override_);
 
   // Add channel to the request URL.
   version_info::Channel channel = client_->GetChannelForVariations();
@@ -949,6 +951,13 @@ void VariationsService::StartRepeatedVariationsSeedFetchForTesting() {
   return StartRepeatedVariationsSeedFetch();
 }
 
+void VariationsService::OverridePlatform(
+    Study::Platform platform,
+    const std::string& osname_server_param_override) {
+  field_trial_creator_.OverrideVariationsPlatform(platform);
+  osname_server_param_override_ = osname_server_param_override;
+}
+
 std::string VariationsService::GetOverriddenPermanentCountry() {
   return local_state_->GetString(prefs::kVariationsPermanentOverriddenCountry);
 }

components/variations/service/variations_service.h

@@ -219,6 +219,12 @@ class VariationsService
   // Exposes StartRepeatedVariationsSeedFetch for testing.
   void StartRepeatedVariationsSeedFetchForTesting();
 
+  // Allows the embedder to override the platform and override the OS name in
+  // the variations server url. This is useful for android webview and weblayer
+  // which are distinct from regular android chrome.
+  void OverridePlatform(Study::Platform platform,
+                        const std::string& osname_server_param_override);
+
  protected:
   // Starts the fetching process once, where |OnURLFetchComplete| is called with
   // the response. This calls DoFetchToURL with the set url.
@@ -431,6 +437,10 @@ class VariationsService
   // True if the last request was a retry over http.
   bool last_request_was_http_retry_;
 
+  // When not empty, contains an override for the os name in the variations
+  // server url.
+  std::string osname_server_param_override_;
+
   SEQUENCE_CHECKER(sequence_checker_);
 
   base::WeakPtrFactory<VariationsService> weak_ptr_factory_{this};

components/variations/study_filtering_unittest.cc

@@ -213,13 +213,17 @@ TEST(VariationsStudyFilteringTest, CheckStudyLocale) {
 }
 
 TEST(VariationsStudyFilteringTest, CheckStudyPlatform) {
-  const Study::Platform platforms[] = {
-      Study::PLATFORM_WINDOWS,         Study::PLATFORM_MAC,
-      Study::PLATFORM_LINUX,           Study::PLATFORM_CHROMEOS,
-      Study::PLATFORM_ANDROID,         Study::PLATFORM_IOS,
-      Study::PLATFORM_ANDROID_WEBVIEW, Study::PLATFORM_FUCHSIA};
+  const Study::Platform platforms[] = {Study::PLATFORM_WINDOWS,
+                                       Study::PLATFORM_MAC,
+                                       Study::PLATFORM_LINUX,
+                                       Study::PLATFORM_CHROMEOS,
+                                       Study::PLATFORM_ANDROID,
+                                       Study::PLATFORM_IOS,
+                                       Study::PLATFORM_ANDROID_WEBLAYER,
+                                       Study::PLATFORM_FUCHSIA,
+                                       Study::PLATFORM_ANDROID_WEBVIEW};
   ASSERT_EQ(Study::Platform_ARRAYSIZE, static_cast<int>(base::size(platforms)));
-  bool platform_added[base::size(platforms)] = {0};
+  bool platform_added[base::size(platforms)] = {false};
 
   Study::Filter filter;
 

tools/variations/fieldtrial_to_struct.py

@@ -31,20 +31,21 @@ finally:
   sys.path.pop(0)
 
 _platforms = [
-  'android',
-  'android_webview',
-  'chromeos',
-  'fuchsia',
-  'ios',
-  'linux',
-  'mac',
-  'windows',
+    'android',
+    'android_weblayer',
+    'android_webview',
+    'chromeos',
+    'fuchsia',
+    'ios',
+    'linux',
+    'mac',
+    'windows',
 ]
 
 _form_factors = [
-  'desktop',
-  'phone',
-  'tablet',
+    'desktop',
+    'phone',
+    'tablet',
 ]
 
 # Convert a platform argument to the matching Platform enum value in