Fix ExhaustMemory on clang.

base/process/memory_unittest.cc

Index: base/process/memory_unittest.cc
diff --git a/base/process/memory_unittest.cc b/base/process/memory_unittest.cc
index 0be2d4400633ba75101423e4a452891ddb87d9aa..59cf2006ffdf8d05f81d61c9cee05c7ea1a8badb 100644
--- a/base/process/memory_unittest.cc
+++ b/base/process/memory_unittest.cc
@@ -99,6 +99,16 @@ const int kExitCode = base::win::kOomExceptionCode;
 const char* kOomRegex = "Out of memory";
 const int kExitCode = 1;
 #endif
+
+// See corresponding function in content/renderer/render_frame_impl.cc
+NOINLINE void ExhaustMemory() {
+  volatile void* ptr = nullptr;
+  do {
+    ptr = malloc(0x10000000);
+    base::debug::Alias(&ptr);
+  } while (ptr);
+}
+
 }  // namespace
 
 class OutOfMemoryTest : public testing::Test {
@@ -133,6 +143,13 @@ class OutOfMemoryDeathTest : public OutOfMemoryTest {
   }
 };
 
+TEST_F(OutOfMemoryDeathTest, Exhaust) {
+  ASSERT_EXIT({
+      SetUpInDeathAssert();
+      ExhaustMemory();
+    }, testing::ExitedWithCode(kExitCode), kOomRegex);
+}

[Nico, 2017/01/26 17:56:53]

do we really need this test? it duplicates the function under test and it adds a
death test, which both seems a bit suboptimal. i'd either revert changes to this
file, or make it so that the old cold calls the function that's actually being
tested here.

[Will Harris, 2017/01/26 18:12:44]

I'm not sure I totally understand what you mean by "duplicates the function
under test", but alternatively I could move the test to a browser test and
navigate to the URL instead, would that suffice?

Historically we've been okay with death tests for the memory code (see the rest
of the file), but I agree it's non-optimal to duplicate the ExhaustMemory code
in two places.

+
 TEST_F(OutOfMemoryDeathTest, New) {
   ASSERT_EXIT({
       SetUpInDeathAssert();