Fix for test crash when CollectBasicGraphicsInfo fails.

The reason for change
---------------------
The tests of EXTMultisampleCompatibilityTest will crash if
CollectBasicGraphicsInfo fails. Crash occurs in the following call
graph:

TEST_F(EXTMultisampleCompatibilityTest, (any test))
  gpu::EXTMultisampleCompatibilityTest::IsApplicable()
    gpu::GPUTestBotConfig::CurrentConfigMatches("AMD")
      gpu::GPUTestBotConfig::LoadCurrentConfig(NULL)
        // Due to CollectBasicGraphicsInfo failure,
        // function makes no call SetGPUInfo() and returns true.
        // This will result in empty gpu_vendor_ vector.
        gpu::CollectBasicGraphicsInfo(&my_gpu_info)
          // Returns false for any reason
      gpu::GPUTestBotConfig::Matches(const std::string& = config_data)
        gpu::GPUTestBotConfig::Matches(const GPUConfig& = config)
          // BANG! Segfault trying to access gpu_vendor()[0]

The example of situation, where CollectBasicGraphicsInfo fails, is
a test Mac with no display connected. In this case, the internal call
graph of CollectBasicGraphicsInfo will cause the failure:

  gpu::CollectBasicGraphicsInfo(&my_gpu_info)
   angle::GetSystemInfo(&system_info)
     // Will return false after calling GetActiveGPU()
     angle::{anonimous namespace}::GetActiveGPU(...)
       // GetEntryProperty() following CGDisplayIOServicePort will
       // return false.
       CGDisplayIOServicePort(kCGDirectMainDisplay)
         // Will return MACH_PORT_NULL if display is not connected.

Suggested change
----------------
Check that gpu_vendor_ is empty and bail out early in

gpu: :GPUTestBotConfig::Matches(const GPUConfig&)
Cq-Include-Trybots: master.tryserver.chromium.android:android_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
Change-Id: Id8f325e4155ee928f2988c50240d7517641779f8
Reviewed-on: https://chromium-review.googlesource.com/788851
Commit-Queue: Zhenyao Mo <zmo@chromium.org>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521412}

gpu/config/gpu_test_config.cc

@@ -79,8 +79,7 @@ GPUTestConfig::OS GetCurrentOS() {
 }  // namespace anonymous
 
 GPUTestConfig::GPUTestConfig()
-    : validate_gpu_info_(true),
-      os_(kOsUnknown),
+    : os_(kOsUnknown),
       gpu_device_id_(0),
       build_type_(kBuildTypeUnknown),
       api_(kAPIUnknown) {}
@@ -117,8 +116,6 @@ void GPUTestConfig::set_api(int32_t api) {
 }
 
 bool GPUTestConfig::IsValid() const {
-  if (!validate_gpu_info_)
-    return true;
   if (gpu_device_id_ != 0 && (gpu_vendor_.size() != 1 || gpu_vendor_[0] == 0))
     return false;
   return true;
@@ -153,10 +150,6 @@ bool GPUTestConfig::OverlapsWith(const GPUTestConfig& config) const {
   return true;
 }
 
-void GPUTestConfig::DisableGPUInfoValidation() {
-  validate_gpu_info_ = false;
-}
-
 void GPUTestConfig::ClearGPUVendor() {
   gpu_vendor_.clear();
 }
@@ -170,7 +163,6 @@ void GPUTestBotConfig::AddGPUVendor(uint32_t gpu_vendor) {
 }
 
 bool GPUTestBotConfig::SetGPUInfo(const GPUInfo& gpu_info) {
-  DCHECK(validate_gpu_info_);
   if (gpu_info.gpu.device_id == 0 || gpu_info.gpu.vendor_id == 0)
     return false;
   ClearGPUVendor();
@@ -202,12 +194,10 @@ bool GPUTestBotConfig::IsValid() const {
     default:
       return false;
   }
-  if (validate_gpu_info_) {
-    if (gpu_vendor().size() != 1 || gpu_vendor()[0] == 0)
-      return false;
-    if (gpu_device_id() == 0)
-      return false;
-  }
+  if (gpu_vendor().size() != 1 || gpu_vendor()[0] == 0)
+    return false;
+  if (gpu_device_id() == 0)
+    return false;
   switch (build_type()) {
     case kBuildTypeRelease:
     case kBuildTypeDebug:
@@ -261,8 +251,7 @@ bool GPUTestBotConfig::LoadCurrentConfig(const GPUInfo* gpu_info) {
     CollectInfoResult result = CollectBasicGraphicsInfo(&my_gpu_info);
     if (result != kCollectInfoSuccess) {
       LOG(ERROR) << "Fail to identify GPU";
-      DisableGPUInfoValidation();
-      rt = true;
+      rt = false;
     } else {
       rt = SetGPUInfo(my_gpu_info);
     }

gpu/config/gpu_test_config.h

@@ -83,16 +83,9 @@ class GPU_EXPORT GPUTestConfig {
   // both configs.
   bool OverlapsWith(const GPUTestConfig& config) const;
 
-  // Disable validation of GPU vendor and device ids.
-  void DisableGPUInfoValidation();
-
  protected:
   void ClearGPUVendor();
 
-  // Indicates that the OS has the notion of a numeric GPU vendor and device id
-  // and this data should be validated.
-  bool validate_gpu_info_;
-
  private:
   // operating system.
   int32_t os_;