Add "Search" key press/hold UMA metrics.

ash/common/accelerators/accelerator_router.cc

Index: ash/common/accelerators/accelerator_router.cc
diff --git a/ash/common/accelerators/accelerator_router.cc b/ash/common/accelerators/accelerator_router.cc
index 9b47ee68d08d725cff3ddfa46463910a69e6a51b..fa3fbf122a59667021b82efa8a16fc893d72694a 100644
--- a/ash/common/accelerators/accelerator_router.cc
+++ b/ash/common/accelerators/accelerator_router.cc
@@ -8,6 +8,7 @@
 #include "ash/common/wm/window_state.h"
 #include "ash/common/wm_shell.h"
 #include "ash/common/wm_window.h"
+#include "base/metrics/histogram.h"
 #include "base/stl_util.h"
 #include "ui/base/accelerators/accelerator.h"
 #include "ui/events/event.h"
@@ -49,6 +50,7 @@ bool AcceleratorRouter::ProcessAccelerator(WmWindow* target,
                                            const ui::Accelerator& accelerator) {
   // Callers should never supply null.
   DCHECK(target);
+  RecordSearchKeyStats(accelerator);
   // Special hardware keys like brightness and volume are handled in
   // special way. However, some windows can override this behavior
   // (e.g. Chrome v1 apps by default and Chrome v2 apps with
@@ -65,6 +67,27 @@ bool AcceleratorRouter::ProcessAccelerator(WmWindow* target,
   return WmShell::Get()->accelerator_controller()->Process(accelerator);
 }
 
+void AcceleratorRouter::RecordSearchKeyStats(
+    const ui::Accelerator& accelerator) {
+  if (accelerator.IsCmdDown()) {
+    if (!search_key_pressed_) {
+      search_key_pressed_ = true;
+      search_key_pressed_recorded_ = false;
+      search_key_pressed_timestamp_ = base::TimeTicks::Now();
+    }
+
+    if (accelerator.key_code() != ui::KeyboardCode::VKEY_COMMAND &&
+        !search_key_pressed_recorded_) {
+      search_key_pressed_recorded_ = true;
+      UMA_HISTOGRAM_TIMES(
+          "Keyboard.Shortcuts.CrosSearchKeyDelay",
+          base::TimeTicks::Now() - search_key_pressed_timestamp_);
+    }
+  } else {
+    search_key_pressed_ = false;
+  }
+}
+
 bool AcceleratorRouter::CanConsumeSystemKeys(WmWindow* target,
                                              const ui::KeyEvent& event) {
   // Uses the top level window so if the target is a web contents window the