Gamepad API: add support for connection events

content/common/gamepad_connection_event_message_params.cc

+#include "content/common/gamepad_connection_event_message_params.h"
+
+#include "base/logging.h"
+
+namespace content {
+
+namespace {
+  template <size_t N>
+  size_t StringLengthInBytes(const blink::WebUChar web_string[N]) {
+    size_t i = 0;
+    while (web_string[i] != 0) ++i;
+    DCHECK(i < N);
+    size_t num_characters = i > 0 ? (i - 1) : 0;
+    return num_characters * sizeof(blink::WebUChar);
+  }
+}
+
+GamepadConnectionEventMessageParams::GamepadConnectionEventMessageParams()
+   : index(-1) {
+}
+
+GamepadConnectionEventMessageParams::~GamepadConnectionEventMessageParams() {
+}
+
+GamepadConnectionEventMessageParams::GamepadConnectionEventMessageParams(
+    int index, const blink::WebGamepad& gamepad)
+    : index(index),
+      timestamp(gamepad.timestamp),
+      axes_length(gamepad.axesLength),
+      buttons_length(gamepad.buttonsLength),
+      connected(gamepad.connected) {
+  size_t num_bytes =
+      StringLengthInBytes<blink::WebGamepad::idLengthCap>(gamepad.id);
+  const blink::WebUChar* characters = &gamepad.id[0];
+  id_characters = std::vector<blink::WebUChar>(characters,
+                                               characters + num_bytes);
+
+  num_bytes =
+      StringLengthInBytes<blink::WebGamepad::mappingLengthCap>(gamepad.mapping);
+  characters = &gamepad.mapping[0];
+  mapping_characters = std::vector<blink::WebUChar>(characters,
+                                                    characters + num_bytes);
+}
+
+void GamepadConnectionEventMessageParams::GetWebGamepad(
+    blink::WebGamepad* gamepad) const {
+  DCHECK(index >= 0);
+  DCHECK(id_characters.size() < (blink::WebGamepad::idLengthCap - 1));
+
+  size_t num_bytes = id_characters.size() * sizeof(blink::WebUChar);
+  memcpy(&gamepad->id[0], &id_characters[0], num_bytes);
+  gamepad->id[id_characters.size()] = 0;
+
+  DCHECK(mapping_characters.size() < (blink::WebGamepad::mappingLengthCap - 1));
+  num_bytes = mapping_characters.size() * sizeof(blink::WebUChar);
+  memcpy(&gamepad->mapping[0], &mapping_characters[0], num_bytes);
+  gamepad->mapping[mapping_characters.size()] = 0;
+
+  gamepad->timestamp = timestamp;
+  gamepad->axesLength = axes_length;
+  gamepad->buttonsLength = buttons_length;
+  gamepad->connected = connected;
+}
+
+}