memory coordinator: Set variation parameters if available

chrome/browser/memory/chrome_memory_coordinator_delegate.cc

Index: chrome/browser/memory/chrome_memory_coordinator_delegate.cc
diff --git a/chrome/browser/memory/chrome_memory_coordinator_delegate.cc b/chrome/browser/memory/chrome_memory_coordinator_delegate.cc
index 672b203569a5a65f9071cc5d4eb783f726a64b80..f9677a55a4d11dc93b0a4fbb7b9bd40cb5309013 100644
--- a/chrome/browser/memory/chrome_memory_coordinator_delegate.cc
+++ b/chrome/browser/memory/chrome_memory_coordinator_delegate.cc
@@ -5,11 +5,45 @@
 #include "chrome/browser/memory/chrome_memory_coordinator_delegate.h"
 
 #include "base/memory/ptr_util.h"
+#include "base/strings/string_number_conversions.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/memory/tab_manager.h"
+#include "components/variations/variations_associated_data.h"
 
 namespace memory {
 
+namespace {
+
+void SetIntVariationParameter(
+    const std::map<std::string, std::string> variations,
+    const char* name,
+    int* target) {
+  const auto& iter = variations.find(name);
+  if (iter == variations.end())
+    return;
+  int value;
+  if (!iter->second.empty() && base::StringToInt(iter->second, &value)) {
+    DCHECK(value > 0);
+    *target = value;
+  }
+}
+
+void SetSecondsVariationParameter(
+    const std::map<std::string, std::string> variations,
+    const char* name,
+    base::TimeDelta* target) {
+  const auto& iter = variations.find(name);
+  if (iter == variations.end())
+    return;
+  int value;
+  if (!iter->second.empty() && base::StringToInt(iter->second, &value)) {
+    DCHECK(value > 0);
+    *target = base::TimeDelta::FromSeconds(value);
+  }
+}
+
+}  // namespace
+
 // static
 std::unique_ptr<content::MemoryCoordinatorDelegate>
 ChromeMemoryCoordinatorDelegate::Create() {
@@ -31,4 +65,26 @@ bool ChromeMemoryCoordinatorDelegate::CanSuspendBackgroundedRenderer(
 #endif
 }
 
+void ChromeMemoryCoordinatorDelegate::OverrideParameters(
+    content::MemoryCoordinatorV0Params* params) {
+  // Override default parameters with variations.
+  static constexpr char kMemoryCoordinatorV0Trial[] = "MemoryCoordinatorV0";

[bashi, 2016/11/18 20:07:27]

I added "V0" suffix because we might want to do different experiments in the
future.

+  std::map<std::string, std::string> variations;
+  variations::GetVariationParams(kMemoryCoordinatorV0Trial, &variations);
+  SetIntVariationParameter(variations, "expected_renderer_size",
+                           &params->expected_renderer_size);
+  SetIntVariationParameter(variations, "new_renderers_until_throttled",
+                           &params->new_renderers_until_throttled);
+  SetIntVariationParameter(variations, "new_renderers_until_suspended",
+                           &params->new_renderers_until_suspended);
+  SetIntVariationParameter(variations, "new_renderers_back_to_normal",
+                           &params->new_renderers_back_to_normal);
+  SetIntVariationParameter(variations, "new_renderers_back_to_throttled",
+                           &params->new_renderers_back_to_throttled);
+  SetSecondsVariationParameter(variations, "minimum_transition_period",
+                               &params->minimum_transition_period);
+  SetSecondsVariationParameter(variations, "monitoring_interval",
+                               &params->monitoring_interval);
+}
+
 }  // namespace memory