[tracing] Turn StackFrame into struct.

base/trace_event/heap_profiler_stack_frame_deduplicator_unittest.cc

Index: base/trace_event/heap_profiler_stack_frame_deduplicator_unittest.cc
diff --git a/base/trace_event/heap_profiler_stack_frame_deduplicator_unittest.cc b/base/trace_event/heap_profiler_stack_frame_deduplicator_unittest.cc
index 72cb743ad0c22162c1804d864de9aae68ea329eb..2215edebb56fd5920eb7ccade2bb103f3dd9f165 100644
--- a/base/trace_event/heap_profiler_stack_frame_deduplicator_unittest.cc
+++ b/base/trace_event/heap_profiler_stack_frame_deduplicator_unittest.cc
@@ -16,11 +16,11 @@ namespace trace_event {
 
 // Define all strings once, because the deduplicator requires pointer equality,
 // and string interning is unreliable.
-const char kBrowserMain[] = "BrowserMain";
-const char kRendererMain[] = "RendererMain";
-const char kCreateWidget[] = "CreateWidget";
-const char kInitialize[] = "Initialize";
-const char kMalloc[] = "malloc";
+StackFrame kBrowserMain = StackFrame::FromTraceEventName("BrowserMain");
+StackFrame kRendererMain = StackFrame::FromTraceEventName("RendererMain");
+StackFrame kCreateWidget = StackFrame::FromTraceEventName("CreateWidget");
+StackFrame kInitialize = StackFrame::FromTraceEventName("Initialize");
+StackFrame kMalloc = StackFrame::FromTraceEventName("malloc");
 
 TEST(StackFrameDeduplicatorTest, SingleBacktrace) {
   StackFrame bt[] = {kBrowserMain, kCreateWidget, kMalloc};
@@ -47,6 +47,35 @@ TEST(StackFrameDeduplicatorTest, SingleBacktrace) {
   ASSERT_EQ(iter + 3, dedup->end());
 }
 
+TEST(StackFrameDeduplicatorTest, SingleBacktraceWithNull) {
+  StackFrame null_frame = StackFrame::FromTraceEventName(nullptr);
+  StackFrame bt[] = {kBrowserMain, null_frame, kMalloc};
+
+  // Deduplicator doesn't care about what's inside StackFrames,
+  // and handles nullptr StackFrame values as any other.
+  //
+  // So the call tree should look like this (index in brackets).
+  //
+  // BrowserMain [0]
+  //   (null) [1]
+  //     malloc [2]
+
+  std::unique_ptr<StackFrameDeduplicator> dedup(new StackFrameDeduplicator);
+  ASSERT_EQ(2, dedup->Insert(std::begin(bt), std::end(bt)));
+
+  auto iter = dedup->begin();
+  ASSERT_EQ(kBrowserMain, (iter + 0)->frame);
+  ASSERT_EQ(-1, (iter + 0)->parent_frame_index);
+
+  ASSERT_EQ(null_frame, (iter + 1)->frame);
+  ASSERT_EQ(0, (iter + 1)->parent_frame_index);
+
+  ASSERT_EQ(kMalloc, (iter + 2)->frame);
+  ASSERT_EQ(1, (iter + 2)->parent_frame_index);
+
+  ASSERT_EQ(iter + 3, dedup->end());
+}
+
 // Test that there can be different call trees (there can be multiple bottom
 // frames). Also verify that frames with the same name but a different caller
 // are represented as distinct nodes.
@@ -119,17 +148,5 @@ TEST(StackFrameDeduplicatorTest, Deduplication) {
   ASSERT_EQ(dedup->begin() + 3, dedup->end());
 }
 
-TEST(StackFrameDeduplicatorTest, NullPaddingIsRemoved) {
-  StackFrame bt0[] = {kBrowserMain, nullptr, nullptr, nullptr};
-
-  std::unique_ptr<StackFrameDeduplicator> dedup(new StackFrameDeduplicator);
-
-  // There are four frames in the backtrace, but the null pointers should be
-  // skipped, so only one frame is inserted, which will have index 0.
-  ASSERT_EQ(4u, arraysize(bt0));
-  ASSERT_EQ(0, dedup->Insert(std::begin(bt0), std::end(bt0)));
-  ASSERT_EQ(dedup->begin() + 1, dedup->end());
-}
-
 }  // namespace trace_event
 }  // namespace base