content: Remove non-thread-safe use of WeakPtrs.

Instead of avoiding to send IPC from ChildDiscardableSharedMemoryManager
dtor, make sure ThreadSafeSender instance is still valid at the
time dtor is called.

BUG=471246

Review URL: https://codereview.chromium.org/1035313002

Cr-Commit-Position: refs/heads/master@{#322665}

3 files changed, 12 insertions, 15 deletions

diff --git a/content/child/child_discardable_shared_memory_manager.cc b/content/child/child_discardable_shared_memory_manager.cc
index 3b11398..73b4cb1 100644
--- a/content/child/child_discardable_shared_memory_manager.cc
+++ b/content/child/child_discardable_shared_memory_manager.cc
@@ -72,17 +72,20 @@ class DiscardableMemoryImpl : public base::DiscardableMemory {
   DISALLOW_COPY_AND_ASSIGN(DiscardableMemoryImpl);
 };
 
+void SendDeletedDiscardableSharedMemoryMessage(
+    scoped_refptr<ThreadSafeSender> sender,
+    DiscardableSharedMemoryId id) {
+  sender->Send(new ChildProcessHostMsg_DeletedDiscardableSharedMemory(id));
+}
+
 }  // namespace
 
 ChildDiscardableSharedMemoryManager::ChildDiscardableSharedMemoryManager(
     ThreadSafeSender* sender)
-    : heap_(base::GetPageSize()), sender_(sender), weak_ptr_factory_(this) {
+    : heap_(base::GetPageSize()), sender_(sender) {
 }
 
 ChildDiscardableSharedMemoryManager::~ChildDiscardableSharedMemoryManager() {
-  // Cancel all DeletedDiscardableSharedMemory callbacks.
-  weak_ptr_factory_.InvalidateWeakPtrs();
-
   // TODO(reveman): Determine if this DCHECK can be enabled. crbug.com/430533
   // DCHECK_EQ(heap_.GetSize(), heap_.GetSizeOfFreeLists());
   if (heap_.GetSize())
@@ -168,9 +171,7 @@ ChildDiscardableSharedMemoryManager::AllocateLockedDiscardableMemory(
   // Create span for allocated memory.
   scoped_ptr<DiscardableSharedMemoryHeap::Span> new_span(heap_.Grow(
       shared_memory.Pass(), allocation_size_in_bytes,
-      base::Bind(
-          &ChildDiscardableSharedMemoryManager::DeletedDiscardableSharedMemory,
-          weak_ptr_factory_.GetWeakPtr(), new_id)));
+      base::Bind(&SendDeletedDiscardableSharedMemoryMessage, sender_, new_id)));
 
   // Unlock and insert any left over memory into free lists.
   if (pages < pages_to_allocate) {
@@ -272,11 +273,6 @@ ChildDiscardableSharedMemoryManager::AllocateLockedDiscardableSharedMemory(
   return memory.Pass();
 }
 
-void ChildDiscardableSharedMemoryManager::DeletedDiscardableSharedMemory(
-    DiscardableSharedMemoryId id) {
-  sender_->Send(new ChildProcessHostMsg_DeletedDiscardableSharedMemory(id));
-}
-
 void ChildDiscardableSharedMemoryManager::MemoryUsageChanged(
     size_t new_bytes_total,
     size_t new_bytes_free) const {
diff --git a/content/child/child_discardable_shared_memory_manager.h b/content/child/child_discardable_shared_memory_manager.h
index 3dee173..881b59e 100644
--- a/content/child/child_discardable_shared_memory_manager.h
+++ b/content/child/child_discardable_shared_memory_manager.h
@@ -7,7 +7,6 @@
 
 #include "base/memory/discardable_memory_allocator.h"
 #include "base/memory/ref_counted.h"
-#include "base/memory/weak_ptr.h"
 #include "base/synchronization/lock.h"
 #include "content/child/thread_safe_sender.h"
 #include "content/common/content_export.h"
@@ -39,14 +38,12 @@ class CONTENT_EXPORT ChildDiscardableSharedMemoryManager
   scoped_ptr<base::DiscardableSharedMemory>
   AllocateLockedDiscardableSharedMemory(size_t size,
                                         DiscardableSharedMemoryId id);
-  void DeletedDiscardableSharedMemory(DiscardableSharedMemoryId id);
   void MemoryUsageChanged(size_t new_bytes_allocated,
                           size_t new_bytes_free) const;
 
   mutable base::Lock lock_;
   DiscardableSharedMemoryHeap heap_;
   scoped_refptr<ThreadSafeSender> sender_;
-  base::WeakPtrFactory<ChildDiscardableSharedMemoryManager> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ChildDiscardableSharedMemoryManager);
 };
diff --git a/content/child/child_thread_impl.cc b/content/child/child_thread_impl.cc
index 41c5543..c82f791 100644
--- a/content/child/child_thread_impl.cc
+++ b/content/child/child_thread_impl.cc
@@ -477,6 +477,10 @@ void ChildThreadImpl::Init(const Options& options) {
 }
 
 ChildThreadImpl::~ChildThreadImpl() {
+  // ChildDiscardableSharedMemoryManager has to be destroyed while
+  // |thread_safe_sender_| is still valid.
+  discardable_shared_memory_manager_.reset();
+
 #if defined(OS_ANDROID)
   {
     base::AutoLock lock(g_lazy_child_thread_lock.Get());