Extensions: Deprecate the plugins requirement.

NPAPI plugin support has been removed from chrome and the "plugins" extension
manifest key is effectively deprecated. This CL deprecates the plugins
requirement. Extensions which specify the plugins requirements will now get an
install warning. Extensions explicitly requesting the npapi requirement (by
setting requirements.plugins.npapi to true) in their manifest will get a load
error.

BUG=732590

Change-Id: I874ca17b5143516f1746fff90197243eb6ac2999
Reviewed-on: https://chromium-review.googlesource.com/795361
Reviewed-by: Devlin <[email protected]>
Commit-Queue: Karan Bhatia <[email protected]>
Cr-Commit-Position: refs/heads/master@{#521122}
diff --git a/extensions/browser/requirements_checker_unittest.cc b/extensions/browser/requirements_checker_unittest.cc
index c2754322..3bd077f 100644
--- a/extensions/browser/requirements_checker_unittest.cc
+++ b/extensions/browser/requirements_checker_unittest.cc
@@ -36,14 +36,6 @@
     false;
 #endif
 
-// Whether this build supports the plugins.npapi requirement.
-const bool kSupportsNPAPI =
-#if defined(OS_POSIX) && !defined(OS_MACOSX)
-    false;
-#else
-    true;
-#endif
-
 // Returns true if a WebGL check might not fail immediately.
 bool MightSupportWebGL() {
   return content::GpuDataManager::GetInstance()->GpuAccessAllowed(nullptr);
@@ -87,10 +79,6 @@
     manifest_dict_->SetBoolean("requirements.window.shape", true);
   }
 
-  void RequireNPAPI() {
-    manifest_dict_->SetBoolean("requirements.plugins.npapi", true);
-  }
-
   void RequireFeature(const char feature[]) {
     if (!manifest_dict_->HasKey(kFeaturesKey))
       manifest_dict_->Set(kFeaturesKey, std::make_unique<base::ListValue>());
@@ -120,8 +108,7 @@
 TEST_F(RequirementsCheckerTest, RequirementsSuccess) {
   if (kSupportsWindowShape)
     RequireWindowShape();
-  if (kSupportsNPAPI)
-    RequireNPAPI();
+
   RequireFeature(kFeatureCSS3d);
 
   CreateExtension();
@@ -138,10 +125,6 @@
     RequireWindowShape();
     expected_errors++;
   }
-  if (!kSupportsNPAPI) {
-    RequireNPAPI();
-    expected_errors++;
-  }
   if (!MightSupportWebGL()) {
     RequireFeature(kFeatureWebGL);
     expected_errors++;