Sampling Heap Profiler: Expose browser heap sampling profiles over DT protocol

The Memory.getBrowserSamplingProfile command is introduced.

BUG=803276

Change-Id: I4cc1ede9ace572971102b681f5d9e9bc693e08f0
Reviewed-on: https://chromium-review.googlesource.com/912323
Commit-Queue: Alexei Filippov <alph@chromium.org>
Reviewed-by: Pavel Feldman <pfeldman@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#535969}

content/browser/devtools/protocol/memory_handler.cc

@@ -7,6 +7,7 @@
 #include "base/memory/memory_pressure_listener.h"
 #include "base/strings/stringprintf.h"
 #include "content/public/common/content_features.h"
+#include "third_party/WebKit/common/sampling_heap_profiler/sampling_heap_profiler.h"
 
 namespace content {
 namespace protocol {
@@ -21,6 +22,29 @@ void MemoryHandler::Wire(UberDispatcher* dispatcher) {
   Memory::Dispatcher::wire(dispatcher, this);
 }
 
+Response MemoryHandler::GetBrowserSamplingProfile(
+    std::unique_ptr<Memory::SamplingProfile>* out_profile) {
+  std::unique_ptr<Array<Memory::SamplingProfileNode>> samples =
+      Array<Memory::SamplingProfileNode>::create();
+  std::vector<blink::SamplingHeapProfiler::Sample> raw_samples =
+      blink::SamplingHeapProfiler::GetInstance()->GetSamples(0);
+
+  for (auto& sample : raw_samples) {
+    std::unique_ptr<Array<String>> stack = Array<String>::create();
+    for (auto* frame : sample.stack)
+      stack->addItem(base::StringPrintf("%p", frame));
+    samples->addItem(Memory::SamplingProfileNode::Create()
+                         .SetSize(sample.size)
+                         .SetCount(sample.count)
+                         .SetStack(std::move(stack))
+                         .Build());
+  }
+
+  *out_profile =
+      Memory::SamplingProfile::Create().SetSamples(std::move(samples)).Build();
+  return Response::OK();
+}
+
 Response MemoryHandler::SetPressureNotificationsSuppressed(
     bool suppressed) {
   if (base::FeatureList::IsEnabled(features::kMemoryCoordinator)) {

content/browser/devtools/protocol/memory_handler.h

@@ -20,6 +20,8 @@ class MemoryHandler : public DevToolsDomainHandler,
 
   void Wire(UberDispatcher* dispatcher) override;
 
+  Response GetBrowserSamplingProfile(
+      std::unique_ptr<Memory::SamplingProfile>* out_profile) override;
   Response SetPressureNotificationsSuppressed(bool suppressed) override;
   Response SimulatePressureNotification(const std::string& level) override;
 

content/browser/devtools/protocol_config.json

@@ -36,7 +36,7 @@
             },
             {
                 "domain": "Memory",
-                "include": ["setPressureNotificationsSuppressed", "simulatePressureNotification"]
+                "include": ["getBrowserSamplingProfile", "setPressureNotificationsSuppressed", "simulatePressureNotification"]
             },
             {
                 "domain": "Network",

content/browser/devtools/render_frame_devtools_agent_host.cc

@@ -23,6 +23,7 @@
 #include "content/browser/devtools/protocol/input_handler.h"
 #include "content/browser/devtools/protocol/inspector_handler.h"
 #include "content/browser/devtools/protocol/io_handler.h"
+#include "content/browser/devtools/protocol/memory_handler.h"
 #include "content/browser/devtools/protocol/network_handler.h"
 #include "content/browser/devtools/protocol/page_handler.h"
 #include "content/browser/devtools/protocol/protocol.h"
@@ -329,6 +330,7 @@ void RenderFrameDevToolsAgentHost::AttachSession(DevToolsSession* session) {
   session->AddHandler(base::WrapUnique(new protocol::InspectorHandler()));
   session->AddHandler(base::WrapUnique(new protocol::IOHandler(
       GetIOContext())));
+  session->AddHandler(base::WrapUnique(new protocol::MemoryHandler()));
   session->AddHandler(base::WrapUnique(new protocol::NetworkHandler(GetId())));
   session->AddHandler(base::WrapUnique(new protocol::SchemaHandler()));
   session->AddHandler(base::WrapUnique(new protocol::ServiceWorkerHandler()));

third_party/WebKit/Source/core/inspector/browser_protocol.json

@@ -6999,7 +6999,17 @@
                 },
                 {
                     "name": "getAllTimeSamplingProfile",
-                    "description": "Retrieve native memory allocations profile collected since process startup.",
+                    "description": "Retrieve native memory allocations profile\ncollected since renderer process startup.",
+                    "returns": [
+                        {
+                            "name": "profile",
+                            "$ref": "SamplingProfile"
+                        }
+                    ]
+                },
+                {
+                    "name": "getBrowserSamplingProfile",
+                    "description": "Retrieve native memory allocations profile\ncollected since browser process startup.",
                     "returns": [
                         {
                             "name": "profile",

third_party/WebKit/Source/core/inspector/browser_protocol.pdl

@@ -1019,7 +1019,7 @@ experimental domain CSS
   # Enables the selector recording.
   command startRuleUsageTracking
 
-  # Stop tracking rule usage and return the list of rules that were used since last call to 
+  # Stop tracking rule usage and return the list of rules that were used since last call to
   # `takeCoverageDelta` (or since start of coverage instrumentation)
   command stopRuleUsageTracking
     returns
@@ -3166,11 +3166,18 @@ experimental domain Memory
   # Stop collecting native memory profile.
   command stopSampling
 
-  # Retrieve native memory allocations profile collected since process startup.
+  # Retrieve native memory allocations profile
+  # collected since renderer process startup.
   command getAllTimeSamplingProfile
     returns
       SamplingProfile profile
 
+  # Retrieve native memory allocations profile
+  # collected since browser process startup.
+  command getBrowserSamplingProfile
+    returns
+      SamplingProfile profile
+
   # Retrieve native memory allocations profile collected since last
   # `startSampling` call.
   command getSamplingProfile