Prerender: Allow on low end devices for ORIGIN_OFFLINE

chrome/browser/prerender/prerender_unittest.cc

Index: chrome/browser/prerender/prerender_unittest.cc
diff --git a/chrome/browser/prerender/prerender_unittest.cc b/chrome/browser/prerender/prerender_unittest.cc
index 9eed34f007b685d0d6451ad717db9b6ce2b6ae40..46debd9a70fa57dc69285fa6585351e399ac6ddf 100644
--- a/chrome/browser/prerender/prerender_unittest.cc
+++ b/chrome/browser/prerender/prerender_unittest.cc
@@ -216,6 +216,13 @@ class UnitTestPrerenderManager : public PrerenderManager {
     prerender_contents_map_.erase(std::make_pair(child_id, route_id));
   }
 
+  void SetIsLowEndDevice(bool is_low_end_device) {
+    is_low_end_device_ = is_low_end_device;
+  }
+
+ protected:
+  bool IsLowEndDevice() override { return is_low_end_device_; }

[mmenke, 2016/08/03 15:10:58]

Doesn't really matter, but this can be private

[pasko, 2016/08/03 15:30:18]

Done.

+
  private:
   DummyPrerenderContents* SetNextPrerenderContents(
       std::unique_ptr<DummyPrerenderContents> prerender_contents) {
@@ -244,6 +251,7 @@ class UnitTestPrerenderManager : public PrerenderManager {
   Time time_;
   TimeTicks time_ticks_;
   std::unique_ptr<PrerenderContents> next_prerender_contents_;
+  bool is_low_end_device_;
 };
 
 class RestorePrerenderMode {
@@ -322,6 +330,8 @@ class PrerenderTest : public testing::Test {
     prerender_manager_->Shutdown();
   }
 
+  void SetUp() override { prerender_manager()->SetIsLowEndDevice(false); }

[mmenke, 2016/08/03 15:10:58]

Can just put this in the constructor.  Each test iteration uses its own instance
of the test fixture (Which means SetUp is mostly just useful for interleaving
subclass and superclass initialization)

[pasko, 2016/08/03 15:30:17]

Ah, there is some stuff already in the constructor, putting it there then, will
look more consistent. I forgot that TEST_F re-creates the fixture (shame shame).

Though, how does this align with general perception of doing work in
constructors being more error prone?
https://google.github.io/styleguide/cppguide.html#Doing_Work_in_Constructors

[mmenke, 2016/08/03 15:36:43]

We aren't doing any virtual calls to the test fixture, and we can't fail (If we
could fail, EXPECTs work fine in the constructor, ASSERTs would have to go here,
though).

My feeling is that in test fixtures, it's best just to do all the work in the
constructor/destructor, to have everything all in one place.

+
   UnitTestPrerenderManager* prerender_manager() {
     return prerender_manager_.get();
   }
@@ -437,6 +447,29 @@ TEST_F(PrerenderTest, OfflinePrerenderIgnoresThirdPartyCookiesPref) {
   EXPECT_EQ(ORIGIN_OFFLINE, prerender_handle->contents()->origin());
 }
 
+TEST_F(PrerenderTest, PrerenderDisabledOnLowEndDevice) {
+  GURL url("http://www.google.com/");
+  ASSERT_TRUE(PrerenderManager::IsPrerenderingPossible());
+  prerender_manager()->SetIsLowEndDevice(true);
+  EXPECT_FALSE(AddSimplePrerender(url));
+}
+
+TEST_F(PrerenderTest, OfflinePrerenderPossibleOnLowEndDevice) {
+  GURL url("http://www.google.com/");
+  ASSERT_TRUE(PrerenderManager::IsPrerenderingPossible());
+
+  prerender_manager()->SetIsLowEndDevice(true);
+
+  DummyPrerenderContents* prerender_contents =
+      prerender_manager()->CreateNextPrerenderContents(
+          url, ORIGIN_OFFLINE, FINAL_STATUS_MANAGER_SHUTDOWN);
+  std::unique_ptr<PrerenderHandle> prerender_handle(
+      prerender_manager()->AddPrerenderForOffline(url, nullptr, kSize));
+  EXPECT_TRUE(prerender_handle);
+  EXPECT_TRUE(prerender_handle->IsPrerendering());
+  EXPECT_TRUE(prerender_contents->prerendering_has_started());
+}
+
 TEST_F(PrerenderTest, FoundTest) {
   GURL url("http://www.google.com/");
   DummyPrerenderContents* prerender_contents =