Move process-per-site logic from BrowsingInstance to RenderProcessHost.
This avoids sharing SiteInstances across different BrowsingInstances.

BUG=11629
BUG=131676
TEST=See repro steps in http://crbug.com/131676.


Review URL: https://chromiumcodereview.appspot.com/10575014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@144911 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/extensions/process_management_browsertest.cc b/chrome/browser/extensions/process_management_browsertest.cc
index 9eac07c..048792c 100644
--- a/chrome/browser/extensions/process_management_browsertest.cc
+++ b/chrome/browser/extensions/process_management_browsertest.cc
@@ -157,6 +157,8 @@
   EXPECT_NE(ntp1_host, extension1_host);
 
   // Hosted apps only share with each other.
+  // Note that hosted2_host's app has the background permission and will use
+  // process-per-site mode, but it should still share with hosted1_host's app.
   EXPECT_EQ(hosted1_host, hosted2_host);
   EXPECT_NE(hosted1_host, web1_host);
   EXPECT_NE(hosted1_host, extension1_host);