Do not record CPU profile samples when stack collection is failed.

src/profiler/profile-generator.cc

Index: src/profiler/profile-generator.cc
diff --git a/src/profiler/profile-generator.cc b/src/profiler/profile-generator.cc
index 4c4205290fd0f677a4b8b876637fcc0f4fbffad0..2bb47f199db7c65729ec9e846d6fce7bb84726a3 100644
--- a/src/profiler/profile-generator.cc
+++ b/src/profiler/profile-generator.cc
@@ -636,10 +636,9 @@ void ProfileGenerator::RecordTickSample(const TickSample& sample) {
       }
     }
 
-    for (const Address* stack_pos = sample.stack,
-           *stack_end = stack_pos + sample.frames_count;
-         stack_pos != stack_end;
-         ++stack_pos) {
+    for (const Address *stack_pos = sample.stack,

[titzer, 2016/02/19 09:28:37]

Formatting artifact? git cl format should have fixed this.

[alph, 2016/02/19 16:24:29]

So it did.
I hope you don't think I reformatted that manually? ;-)

[titzer, 2016/02/19 16:36:33]

I just asked because it looks backwards to our normal formatting of the star
sticking to the left (i.e. to the type).

+                       *stack_end = stack_pos + sample.frames_count;
+         stack_pos != stack_end; ++stack_pos) {
       *entry = code_map_.FindEntry(*stack_pos);
 
       // Skip unresolved frames (e.g. internal frame) and get source line of