Refactoring: Move some classes from content/child to platform

third_party/WebKit/public/platform/WebProcessMemoryDump.h

Index: third_party/WebKit/public/platform/WebProcessMemoryDump.h
diff --git a/third_party/WebKit/public/platform/WebProcessMemoryDump.h b/third_party/WebKit/public/platform/WebProcessMemoryDump.h
index 29403293667c839c6d37356101d476b178a2b91a..432ab947b0d9a0d11303de1f9e7ade675a2b647f 100644
--- a/third_party/WebKit/public/platform/WebProcessMemoryDump.h
+++ b/third_party/WebKit/public/platform/WebProcessMemoryDump.h
@@ -14,6 +14,9 @@
 class SkTraceMemoryDump;
 
 namespace base {
+
+class DiscardableMemory;
+
 namespace trace_event {
 
 class ProcessMemoryDump;
@@ -114,6 +117,12 @@ public:
         return nullptr;
     }
 
+    virtual blink::WebMemoryAllocatorDump* createDiscardableMemoryAllocatorDump(const std::string& name, base::DiscardableMemory* discardable)
+    {
+        BLINK_ASSERT_NOT_REACHED();
+        return nullptr;
+    }
+
     // Dumps heap memory usage. |allocatorName| is used as an absolute name for
     // base::trace_event::ProcessMemoryDump::AddHeapDump.
     virtual void dumpHeapUsage(const base::hash_map<base::trace_event::AllocationContext, size_t>& bytesByContext, base::trace_event::TraceEventMemoryOverhead& overhead, const char* allocatorName)