Change Win32k PPAPI lockdown to use finch params for mime type.

content/browser/ppapi_plugin_process_host.cc

Index: content/browser/ppapi_plugin_process_host.cc
diff --git a/content/browser/ppapi_plugin_process_host.cc b/content/browser/ppapi_plugin_process_host.cc
index 766a71390626c82162264baea8000721580708f6..ff3422fdc853f223300237160e2e5e395a9060c6 100644
--- a/content/browser/ppapi_plugin_process_host.cc
+++ b/content/browser/ppapi_plugin_process_host.cc
@@ -90,11 +90,14 @@ class PpapiPluginSandboxedProcessLauncherDelegate
       return false;
 
 #if !defined(NACL_WIN64)
-    for (const auto& mime_type : info_.mime_types) {
-      if (IsWin32kLockdownEnabledForMimeType(mime_type.mime_type)) {
-        if (!AddWin32kLockdownPolicy(policy))
-          return false;
-        break;
+    if (IsWin32kRendererLockdownEnabled()) {
+      for (const auto& mime_type : info_.mime_types) {
+        if (GetContentClient()->browser()->IsWin32kLockdownEnabledForMimeType(

[Alexei Svitkine (slow), 2016/01/26 08:23:40]

Nit: Store the result of GetContentClient()->browser() in a var outside the
loop.

[jam, 2016/01/26 15:18:51]

given that the list of mime types should be pretty small, why do this without
seeing that it's slow?

[Will Harris, 2016/01/26 22:57:54]

GetContentClient() does seem to do a CALL and it's done twice (once here and
once below) so saving to a stack variable seems like a reasonable optimization.

+                mime_type.mime_type)) {
+          if (!AddWin32kLockdownPolicy(policy))
+            return false;
+          break;
+        }
       }
     }
 #endif