Make the low priority iframe flag affect all resources in cross origin iframes

Currently it affects all iframes, but only the main resource.

BUG=

Review URL: https://codereview.chromium.org/1328763002

git-svn-id: svn://svn.chromium.org/blink/trunk@201843 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/core/loader/FrameFetchContext.cpp

@@ -689,7 +689,8 @@ ResourceLoadPriority FrameFetchContext::modifyPriorityForExperiments(ResourceLoa
     if (!frame()->settings())
         return priority;
 
-    if (!frame()->isMainFrame() && frame()->settings()->lowPriorityIframes() && type == Resource::MainResource)
+    // If enabled, drop the priority of all resources in a subframe.
+    if (frame()->settings()->lowPriorityIframes() && !frame()->isMainFrame())
         return ResourceLoadPriorityVeryLow;
 
     // Async/Defer scripts.

third_party/WebKit/Source/core/loader/FrameFetchContextTest.cpp

@@ -431,7 +431,6 @@ TEST_F(FrameFetchContextTest, ModifyPriorityForExperiments)
     settings->setFEtchIncreaseFontPriority(false);
     settings->setFEtchDeferLateScripts(false);
     settings->setFEtchIncreasePriorities(false);
-    settings->setLowPriorityIframes(false);
 
     // Base case, no priority change. Note that this triggers m_imageFetched, which will matter for setFetchDeferLateScripts() case below.
     EXPECT_EQ(ResourceLoadPriorityLow, fetchContext->modifyPriorityForExperiments(ResourceLoadPriorityLow, Resource::Image, request));
@@ -479,12 +478,6 @@ TEST_F(FrameFetchContextTest, ModifyPriorityForExperiments)
     settings->setFEtchIncreaseAsyncScriptPriority(true);
     EXPECT_EQ(ResourceLoadPriorityMedium, fetchContext->modifyPriorityForExperiments(ResourceLoadPriorityMedium, Resource::Script, deferredRequest));
 
-    // Set up a child frame, test main resource load with and without setLowPriorityIframes()
-    FrameFetchContext* childFetchContext = createChildFrame();
-    EXPECT_EQ(ResourceLoadPriorityVeryHigh, childFetchContext->modifyPriorityForExperiments(ResourceLoadPriorityVeryHigh, Resource::MainResource, request));
-    settings->setLowPriorityIframes(true);
-    EXPECT_EQ(ResourceLoadPriorityVeryLow, childFetchContext->modifyPriorityForExperiments(ResourceLoadPriorityVeryHigh, Resource::MainResource, request));
-
     // Ensure we don't go out of bounds
     settings->setFEtchIncreasePriorities(true);
     EXPECT_EQ(ResourceLoadPriorityVeryHigh, fetchContext->modifyPriorityForExperiments(ResourceLoadPriorityVeryHigh, Resource::Script, request));
@@ -493,4 +486,21 @@ TEST_F(FrameFetchContextTest, ModifyPriorityForExperiments)
     EXPECT_EQ(ResourceLoadPriorityVeryLow, fetchContext->modifyPriorityForExperiments(ResourceLoadPriorityVeryLow, Resource::Script, preloadRequest));
 }
 
+TEST_F(FrameFetchContextTest, ModifyPriorityForLowPriorityIframes)
+{
+    Settings* settings = document->frame()->settings();
+    settings->setLowPriorityIframes(false);
+    FetchRequest request(ResourceRequest("http://www.example.com"), FetchInitiatorInfo());
+    FrameFetchContext* childFetchContext = createChildFrame();
+
+    // No low priority iframes, expect default values.
+    EXPECT_EQ(ResourceLoadPriorityVeryHigh, childFetchContext->modifyPriorityForExperiments(ResourceLoadPriorityVeryHigh, Resource::MainResource, request));
+    EXPECT_EQ(ResourceLoadPriorityMedium, childFetchContext->modifyPriorityForExperiments(ResourceLoadPriorityMedium, Resource::Script, request));
+
+    // Low priority iframes enabled, everything should be low priority
+    settings->setLowPriorityIframes(true);
+    EXPECT_EQ(ResourceLoadPriorityVeryLow, childFetchContext->modifyPriorityForExperiments(ResourceLoadPriorityVeryHigh, Resource::MainResource, request));
+    EXPECT_EQ(ResourceLoadPriorityVeryLow, childFetchContext->modifyPriorityForExperiments(ResourceLoadPriorityMedium, Resource::Script, request));
+}
+
 } // namespace