Convert device_sensors to use mojo.

content/browser/device_sensors/data_fetcher_shared_memory_base.cc

Index: content/browser/device_sensors/data_fetcher_shared_memory_base.cc
diff --git a/content/browser/device_sensors/data_fetcher_shared_memory_base.cc b/content/browser/device_sensors/data_fetcher_shared_memory_base.cc
index 053807680fd4f211a38492dbfd3e89b54f4da4d4..314331e48be1ae6c911b829370e5f689e94c5ab1 100644
--- a/content/browser/device_sensors/data_fetcher_shared_memory_base.cc
+++ b/content/browser/device_sensors/data_fetcher_shared_memory_base.cc
@@ -119,9 +119,6 @@ DataFetcherSharedMemoryBase::~DataFetcherSharedMemoryBase() {
   // make sure polling thread stops asap.
   if (polling_thread_)
     polling_thread_->Stop();
-
-  STLDeleteContainerPairSecondPointers(shared_memory_map_.begin(),
-      shared_memory_map_.end());
 }
 
 bool DataFetcherSharedMemoryBase::StartFetchingDeviceData(
@@ -183,16 +180,13 @@ void DataFetcherSharedMemoryBase::Shutdown() {
   StopFetchingDeviceData(CONSUMER_TYPE_LIGHT);
 }
 
-base::SharedMemoryHandle
-DataFetcherSharedMemoryBase::GetSharedMemoryHandleForProcess(
-    ConsumerType consumer_type, base::ProcessHandle process) {
-  SharedMemoryMap::const_iterator it = shared_memory_map_.find(consumer_type);
+mojo::ScopedSharedBufferHandle
+DataFetcherSharedMemoryBase::GetSharedMemoryHandle(ConsumerType consumer_type) {
+  auto it = shared_memory_map_.find(consumer_type);
   if (it == shared_memory_map_.end())
-    return base::SharedMemory::NULLHandle();
+    return mojo::ScopedSharedBufferHandle();

[dcheng, 2016/07/05 02:51:54]

Btw, does reaching this state indicate a logic flaw? It would mean that we
didn't call StartFetchingDeviceData first or it failed, right? Do you think it'd
make sense to DCHECK() instead?

(Just trying to get a sense of the right thing to do here, but if this is a
control path that is exceptional, it might be nice to highlight it as such)

[Sam McNally, 2016/07/05 03:03:36]

Done.

 
-  base::SharedMemoryHandle renderer_handle;
-  it->second->ShareToProcess(process, &renderer_handle);
-  return renderer_handle;
+  return it->second.first->Clone();
 }
 
 bool DataFetcherSharedMemoryBase::InitAndStartPollingThreadIfNecessary() {
@@ -222,34 +216,26 @@ base::TimeDelta DataFetcherSharedMemoryBase::GetInterval() const {
   return base::TimeDelta::FromMicroseconds(kInertialSensorIntervalMicroseconds);
 }
 
-base::SharedMemory* DataFetcherSharedMemoryBase::GetSharedMemory(
+void* DataFetcherSharedMemoryBase::GetSharedMemoryBuffer(
     ConsumerType consumer_type) {
-  SharedMemoryMap::const_iterator it = shared_memory_map_.find(consumer_type);
+  auto it = shared_memory_map_.find(consumer_type);
   if (it != shared_memory_map_.end())
-    return it->second;
+    return it->second.second.get();
 
   size_t buffer_size = GetConsumerSharedMemoryBufferSize(consumer_type);
   if (buffer_size == 0)
     return nullptr;
 
-  std::unique_ptr<base::SharedMemory> new_shared_mem(new base::SharedMemory);
-  if (new_shared_mem->CreateAndMapAnonymous(buffer_size)) {
-    if (void* mem = new_shared_mem->memory()) {
-      memset(mem, 0, buffer_size);
-      base::SharedMemory* shared_mem = new_shared_mem.release();
-      shared_memory_map_[consumer_type] = shared_mem;
-      return shared_mem;
-    }
-  }
-  LOG(ERROR) << "Failed to initialize shared memory";
-  return nullptr;
-}
-
-void* DataFetcherSharedMemoryBase::GetSharedMemoryBuffer(
-    ConsumerType consumer_type) {
-  if (base::SharedMemory* shared_memory = GetSharedMemory(consumer_type))
-    return shared_memory->memory();
-  return nullptr;
+  mojo::ScopedSharedBufferHandle buffer =
+      mojo::SharedBufferHandle::Create(buffer_size);
+  mojo::ScopedSharedBufferMapping mapping = buffer->Map(buffer_size);
+  if (!mapping)
+    return nullptr;
+  void* mem = mapping.get();
+  memset(mem, 0, buffer_size);
+  shared_memory_map_[consumer_type] =
+      std::make_pair(std::move(buffer), std::move(mapping));
+  return mem;
 }
 
 base::MessageLoop* DataFetcherSharedMemoryBase::GetPollingMessageLoop() const {