Store information about invoked RunnableFunction on stack to aid debugging of...

Store information about invoked RunnableFunction on stack to aid debugging of canary channel crashes.

TEST=compiles
BUG=81449
Review URL: http://codereview.chromium.org/7066006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@86447 0039d316-1c4b-4281-b951-d872f2087c98

base/debug/alias.h

@@ -6,13 +6,15 @@
 #define BASE_DEBUG_ALIAS_H_
 #pragma once
 
+#include "base/base_api.h"
+
 namespace base {
 namespace debug {
 
 // Make the optimizer think that var is aliased. This is to prevent it from
 // optimizing out variables that that would not otherwise be live at the point
 // of a potential crash.
-void Alias(const void* var);
+void BASE_API Alias(const void* var);
 
 }  // namespace debug
 }  // namespace base

base/task.h

@@ -7,11 +7,16 @@
 #pragma once
 
 #include "base/base_api.h"
+#include "base/debug/alias.h"
 #include "base/memory/raw_scoped_refptr_mismatch_checker.h"
 #include "base/memory/weak_ptr.h"
 #include "base/tracked.h"
 #include "base/tuple.h"
 
+namespace base {
+const size_t kDeadTask = 0xDEAD7A53;
+}
+
 // Task ------------------------------------------------------------------------
 //
 // A task is a generic runnable thingy, usually used for running code on a
@@ -325,6 +330,7 @@ class RunnableMethod : public CancelableTask {
 
   ~RunnableMethod() {
     ReleaseCallee();
+    obj_ = reinterpret_cast<T*>(base::kDeadTask);
   }
 
   virtual void Run() {
@@ -452,9 +458,18 @@ class RunnableFunction : public Task {
   }
 
   ~RunnableFunction() {
+    function_ = reinterpret_cast<Function>(base::kDeadTask);
   }
 
   virtual void Run() {
+    // TODO(apatrick): Remove this ASAP. This ensures that the function pointer
+    // is available in minidumps for the purpose of diagnosing
+    // http://crbug.com/81449.
+    Function function = function_;
+    base::debug::Alias(&function);
+    Params params = params_;
+    base::debug::Alias(&params);
+
     if (function_)
       DispatchToFunction(function_, params_);
   }