Convert //ppapi to use std::unique_ptr

chrome/browser/renderer_host/pepper/chrome_browser_pepper_host_factory.h

Index: chrome/browser/renderer_host/pepper/chrome_browser_pepper_host_factory.h
diff --git a/chrome/browser/renderer_host/pepper/chrome_browser_pepper_host_factory.h b/chrome/browser/renderer_host/pepper/chrome_browser_pepper_host_factory.h
index b8c28ccd0335a73ce87d4ebd12d7c80e425d997b..735da93c3cabb8c6139971295740ba14a30d1b69 100644
--- a/chrome/browser/renderer_host/pepper/chrome_browser_pepper_host_factory.h
+++ b/chrome/browser/renderer_host/pepper/chrome_browser_pepper_host_factory.h
@@ -18,7 +18,7 @@ class ChromeBrowserPepperHostFactory : public ppapi::host::HostFactory {
   explicit ChromeBrowserPepperHostFactory(content::BrowserPpapiHost* host);
   ~ChromeBrowserPepperHostFactory() override;
 
-  scoped_ptr<ppapi::host::ResourceHost> CreateResourceHost(
+  std::unique_ptr<ppapi::host::ResourceHost> CreateResourceHost(

[dcheng, 2016/04/06 19:57:02]

I ended up changing this too since it's a HostFactory override.

Guiding rules for #includes that I use:

1. Implementation and test .cc files do not need to duplicate headers included
in the 'primary' header.
2. If a class declared in a header has a parent class, the header does not need
to duplicate headers included by the parent class's header when the only
reference is for overriding methods from that parent class. Thus, in this case,
since the only reference is to override a method from HostFactory, no #include
for <memory> is added.

       ppapi::host::PpapiHost* host,
       PP_Resource resource,
       PP_Instance instance,