[Clank SSM]: Enable stack sampling in android browsertests.

android_browsertests must depend on libunwindstack directly instead of
through DFM, since loading of a partitioned library is not supported in
an APK.
(internal discussion)
https://groups.google.com/a/google.com/g/clank-components/c/ktt285Gtax4/m/yRy8qm8LAQAJ

This CL also re-enables tracing use of StackSampingProfiler, which
was accidentally disabled in https://crrev.com/784147?

Bug: 1004855
Change-Id: I5967bf3815008843ba8a77e926977e39a4ccfbd8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2293071Reviewed-by: Wez <wez@chromium.org>
Reviewed-by: Mike Wittman <wittman@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@google.com>
Commit-Queue: Etienne Pierre-Doray <etiennep@chromium.org>
Cr-Commit-Position: refs/heads/master@{#789530}

base/BUILD.gn

@@ -91,11 +91,6 @@ dep_libevent =
 # Determines whether message_pump_libevent should be used.
 use_libevent = dep_libevent && !is_ios
 
-# Whether or not cfi table should be enabled on arm.
-# TODO(crbug.com/1090409): Replace can_unwind_with_cfi_table once sampling
-# profiler is enabled on android.
-enable_arm_cfi_table = is_android && !is_component_build && current_cpu == "arm"
-
 if (is_android) {
   import("//build/config/android/rules.gni")
 }

base/profiler/stack_sampling_profiler.cc

@@ -742,8 +742,9 @@ TimeTicks StackSamplingProfiler::TestPeer::GetNextSampleTime(
 // The profiler is currently only implemented for Windows x64 and MacOSX.
 // TODO(https://crbug.com/1004855): enable for Android arm.
 bool StackSamplingProfiler::IsSupported() {
-#if (defined(OS_WIN) && defined(ARCH_CPU_X86_64)) || \
-    (defined(OS_MACOSX) && defined(ARCH_CPU_X86_64) && !defined(OS_IOS))
+#if (defined(OS_WIN) && defined(ARCH_CPU_X86_64)) ||                        \
+    (defined(OS_MACOSX) && defined(ARCH_CPU_X86_64) && !defined(OS_IOS)) || \
+    (defined(OS_ANDROID) && BUILDFLAG(ENABLE_ARM_CFI_TABLE))
 #if defined(OS_MACOSX)
   // TODO(https://crbug.com/1098119): Fix unwinding on OS X 10.16. The OS
   // has moved all system libraries into the dyld shared cache and this

build/config/compiler/compiler.gni

@@ -172,6 +172,11 @@ assert(!can_unwind_with_frame_pointers || enable_frame_pointers)
 can_unwind_with_cfi_table = is_android && !is_component_build &&
                             !enable_frame_pointers && current_cpu == "arm"
 
+# Whether or not cfi table should be enabled on arm.
+# TODO(crbug.com/1090409): Replace can_unwind_with_cfi_table with this once
+# sampling profiler is enabled on android.
+enable_arm_cfi_table = is_android && !is_component_build && current_cpu == "arm"
+
 declare_args() {
   # Set to true to use lld, the LLVM linker.
   use_lld = is_clang && (!is_ios && !is_mac)

chrome/android/modules/stack_unwinder/internal/BUILD.gn

@@ -52,3 +52,16 @@ component("stack_unwinder") {
     cflags = [ "-fsymbol-partition=stack_unwinder_partition" ]
   }
 }
+
+# Since loading of a partitioned library is not supported in an APK, a separate
+# target without partition is necessary for testing.
+source_set("stack_unwinder_for_testing") {
+  testonly = true
+  sources = [ "stack_unwinder_module_contents_impl.cc" ]
+  deps = [
+    ":jni_headers",
+    "//base",
+    "//base:native_unwinder_android",
+    "//chrome/android/features/stack_unwinder/public:native",
+  ]
+}

chrome/common/profiler/stack_sampling_browsertest.cc

@@ -11,14 +11,20 @@
 #include "base/test/scoped_run_loop_timeout.h"
 #include "base/thread_annotations.h"
 #include "base/threading/platform_thread.h"
+#include "build/build_config.h"
 #include "chrome/common/channel_info.h"
 #include "chrome/common/chrome_switches.h"
-#include "chrome/test/base/in_process_browser_test.h"
 #include "components/metrics/call_stack_profile_metrics_provider.h"
 #include "components/version_info/channel.h"
 #include "content/public/test/browser_test.h"
 #include "third_party/metrics_proto/sampled_profile.pb.h"
 
+#if defined(OS_ANDROID)
+#include "chrome/test/base/android/android_browser_test.h"
+#else
+#include "chrome/test/base/in_process_browser_test.h"
+#endif
+
 namespace {
 
 // Class that intercepts and stores profiles provided to the
@@ -95,7 +101,7 @@ bool MatchesProfile(metrics::SampledProfile::TriggerEvent trigger_event,
          profile.process() == process && profile.thread() == thread;
 }
 
-class StackSamplingBrowserTest : public InProcessBrowserTest {
+class StackSamplingBrowserTest : public PlatformBrowserTest {
  public:
   void SetUp() override {
     // Arrange to intercept the CPU profiles at the time they're provided to the
@@ -104,7 +110,7 @@ class StackSamplingBrowserTest : public InProcessBrowserTest {
         SetCpuInterceptorCallbackForTesting(base::BindRepeating(
             &ProfileInterceptor::Intercept,
             base::Unretained(&ProfileInterceptor::GetInstance())));
-    InProcessBrowserTest::SetUp();
+    PlatformBrowserTest::SetUp();
   }
 
   void SetUpCommandLine(base::CommandLine* command_line) override {
@@ -190,8 +196,15 @@ IN_PROC_BROWSER_TEST_F(StackSamplingBrowserTest,
                              metrics::COMPOSITOR_THREAD));
 }
 
+// Android doesn't have a network service process.
+#if defined(OS_ANDROID)
+#define MAYBE_NetworkServiceProcessIOThread \
+  DISABLED_NetworkServiceProcessIOThread
+#else
+#define MAYBE_NetworkServiceProcessIOThread NetworkServiceProcessIOThread
+#endif
 IN_PROC_BROWSER_TEST_F(StackSamplingBrowserTest,
-                       NetworkServiceProcessIOThread) {
+                       MAYBE_NetworkServiceProcessIOThread) {
   EXPECT_TRUE(WaitForProfile(metrics::SampledProfile::PROCESS_STARTUP,
                              metrics::NETWORK_SERVICE_PROCESS,
                              metrics::IO_THREAD));

chrome/common/profiler/stack_sampling_configuration.cc

@@ -37,17 +37,6 @@ namespace {
 base::LazyInstance<StackSamplingConfiguration>::Leaky g_configuration =
     LAZY_INSTANCE_INITIALIZER;
 
-bool IsProfilerEnabledForChannel() {
-#if BUILDFLAG(GOOGLE_CHROME_BRANDING)
-  // Only run on canary and dev.
-  const version_info::Channel channel = chrome::GetChannel();
-  return channel == version_info::Channel::CANARY ||
-         channel == version_info::Channel::DEV;
-#else
-  return true;
-#endif
-}
-
 // Returns true if the current execution is taking place in the browser process.
 bool IsBrowserProcess() {
   const base::CommandLine* command_line =
@@ -77,6 +66,22 @@ bool IsBrowserTestModeEnabled() {
          switches::kStartStackProfilerBrowserTest;
 }
 
+bool IsProfilerEnabledForChannel() {
+#if defined(OS_ANDROID)
+  // Profiling is only enable in it's own dedicated browser tests on Android.
+  // TODO(crbug.com/1004855): Remove this logic to launch profiler.
+  return IsBrowserTestModeEnabled();
+#endif
+#if BUILDFLAG(GOOGLE_CHROME_BRANDING)
+  // Only run on canary and dev.
+  const version_info::Channel channel = chrome::GetChannel();
+  return channel == version_info::Channel::CANARY ||
+         channel == version_info::Channel::DEV;
+#else
+  return true;
+#endif
+}
+
 bool ShouldEnableProfilerForNextRendererProcess() {
   // Ensure deterministic behavior for testing the profiler itself.
   if (IsBrowserTestModeEnabled())

chrome/test/BUILD.gn

@@ -499,6 +499,26 @@ if (is_android) {
       "base/android/android_browser_test_browsertest_android.cc",
     ]
 
+    # Add unwind tables in android_browsertests apk to support enabling
+    # sampling profiler. The unwind tables are generated from debug info in the
+    # binary. Removing "default_symbols" and adding symbols config removes the
+    # "strip_debug" config that strips the debug info, on android_browsertests
+    # apk.
+    if (enable_arm_cfi_table) {
+      sources += [ "../common/profiler/stack_sampling_browsertest.cc" ]
+      deps += [
+        "//chrome/android/modules/stack_unwinder/internal:java",
+        "//chrome/android/modules/stack_unwinder/internal:stack_unwinder_for_testing",
+      ]
+      configs -= [ "//build/config/compiler:default_symbols" ]
+      if (symbol_level == 2) {
+        configs += [ "//build/config/compiler:symbols" ]
+      } else {
+        configs += [ "//build/config/compiler:minimal_symbols" ]
+      }
+      add_unwind_tables_in_apk = true
+    }
+
     data = [
       "$root_gen_dir/chrome/android/chrome_apk_paks/chrome_100_percent.pak",
       "$root_gen_dir/chrome/android/chrome_apk_paks/locales/en-US.pak",