Fix VirtualMemory::Free in presence of lsan

Adding lsan root unregistration when Free-ing VirtualMemory.

Bug: chromium:787976
Change-Id: I0ef32b4324ff6d7b6192d7e5616081766a0e51a8
Reviewed-on: https://chromium-review.googlesource.com/786995Reviewed-by: Bill Budge <bbudge@chromium.org>
Commit-Queue: Mircea Trofin <mtrofin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49609}

src/allocation.cc

@@ -176,6 +176,9 @@ void VirtualMemory::Free() {
   size_t size = size_;
   CHECK(InVM(address, size));
   Reset();
+#if defined(LEAK_SANITIZER)
+  __lsan_unregister_root_region(address, size);
+#endif
   CHECK(base::OS::Free(address, size));
 }
 

test/unittests/wasm/wasm-heap-unittest.cc

@@ -151,8 +151,6 @@ TEST_F(DisjointAllocationPoolTest, MergingSkipLargerSrcWithGap) {
   CheckLooksLike(a, {{10, 15}, {20, 35}, {36, 40}});
 }
 
-// TODO(chromium:787976): remove conditional compilation when bug is fixed
-#if !LEAK_SANITIZER
 class WasmCodeManagerTest : public TestWithIsolate {
  public:
   using NativeModulePtr = std::unique_ptr<NativeModule>;
@@ -387,7 +385,6 @@ TEST_F(WasmCodeManagerTest, LookupWorksAfterRewrite) {
     CHECK_EQ(code1_1, manager.LookupCode(code1_1->instructions().start()));
   }
 }
-#endif
 
 }  // namespace wasm_heap_unittest
 }  // namespace wasm