Added page to Observatory to display native memory allocation information.

runtime/vm/malloc_hooks.cc

Index: runtime/vm/malloc_hooks.cc
diff --git a/runtime/vm/malloc_hooks.cc b/runtime/vm/malloc_hooks.cc
index d838457889c2eb61561053c0ef251d79534492cb..5f077c39a058e138d7dd7f969d606ab2dde40351 100644
--- a/runtime/vm/malloc_hooks.cc
+++ b/runtime/vm/malloc_hooks.cc
@@ -131,13 +131,15 @@ class MallocLocker : public ValueObject {
 //   -Stack trace corresponding to the location of allocation, if applicable
 class AllocationInfo {
  public:
-  explicit AllocationInfo(intptr_t allocation_size)
-      : sample_(NULL), allocation_size_(allocation_size) {
+  AllocationInfo(uword address, intptr_t allocation_size)
+      : sample_(NULL), address_(address), allocation_size_(allocation_size) {
     // Stack trace collection is disabled when we are in the process of creating
     // the first OSThread in order to prevent deadlocks.
     if (MallocHooksState::ProfilingEnabled() &&
         MallocHooksState::stack_trace_collection_enabled()) {
-      sample_ = Profiler::SampleNativeAllocation(kSkipCount);
+      sample_ = Profiler::SampleNativeAllocation(kSkipCount, address,
+                                                 allocation_size);
+      ASSERT(sample_->native_allocation_address() == address_);
     }
   }
 
@@ -145,7 +147,12 @@ class AllocationInfo {
   intptr_t allocation_size() const { return allocation_size_; }
 
  private:
+  // Note: sample_ is not owned by AllocationInfo, but by the SampleBuffer
+  // created by the profiler. As such, this is only here to track if the sample
+  // is still associated with a native allocation, and its fields are never
+  // accessed from this class.
   Sample* sample_;
+  uword address_;
   intptr_t allocation_size_;
 
   // The number of frames that are generated by the malloc hooks and collection
@@ -154,7 +161,7 @@ class AllocationInfo {
   // malloc_hook_tests.cc might fail, particularily
   // StackTraceMallocHookLengthTest. If this value is updated, please make sure
   // that the MallocHooks test cases pass on all platforms.
-  static const intptr_t kSkipCount = 5;
+  static const intptr_t kSkipCount = 6;
 };
 
 
@@ -405,6 +412,12 @@ Sample* MallocHooks::GetSample(const void* ptr) {
 }
 
 
+bool MallocHooks::NativeAllocationFreed(const void* ptr) {
+  Sample* sample = GetSample(ptr);
+  return (sample == NULL);
+}
+
+
 void MallocHooksState::RecordAllocHook(const void* ptr, size_t size) {
   if (MallocHooksState::IsLockHeldByCurrentThread() ||
       !MallocHooksState::IsOriginalProcess()) {
@@ -416,7 +429,8 @@ void MallocHooksState::RecordAllocHook(const void* ptr, size_t size) {
   // Now that we hold the lock, check to make sure everything is still active.
   if ((ptr != NULL) && MallocHooksState::Active()) {
     MallocHooksState::IncrementHeapAllocatedMemoryInBytes(size);
-    MallocHooksState::address_map()->Insert(ptr, new AllocationInfo(size));
+    MallocHooksState::address_map()->Insert(
+        ptr, new AllocationInfo(reinterpret_cast<uword>(ptr), size));
   }
 }