cleanup: Fix nullability declarations

Cleanup imported from an internal Google migration process, courtesy
of Laura Harker.

Change-Id: I11de518eafe6008938589e5250bdcaf8151267e9

lib/cea/cea_decoder.js

@@ -43,13 +43,13 @@ shaka.cea.CeaDecoder = class {
 
     /**
      * Number of consecutive bad frames decoded on CEA-608.
-     * @private {!number}
+     * @private {number}
      */
     this.badFrames_ = 0;
 
     /**
      * A map containing the stream for each mode.
-     * @private {!Map<!string, !shaka.cea.Cea608DataChannel>}
+     * @private {!Map<string, !shaka.cea.Cea608DataChannel>}
      */
     this.cea608ModeToStream_ = new Map([
       ['CC1', new shaka.cea.Cea608DataChannel(0, 0)], // F1 + C1 -> CC1
@@ -60,20 +60,20 @@ shaka.cea.CeaDecoder = class {
 
     /**
      * The current channel that is active on CEA-608 field 1.
-     * @private {!number}
+     * @private {number}
      */
     this.currentField1Channel_ = 0;
 
     /**
      * The current channel that is active on CEA-608 field 2.
-     * @private {!number}
+     * @private {number}
      */
     this.currentField2Channel_ = 0;
 
     /**
      * Map of service number to CEA-708 services, initially empty. Since there
      * can be up to 63 services, they are created dynamically only when needed.
-     * @private {!Map<!number, shaka.cea.Cea708Service>}
+     * @private {!Map<number, shaka.cea.Cea708Service>}
      */
     this.serviceNumberToService_ = new Map();
 
@@ -360,8 +360,8 @@ shaka.cea.CeaDecoder = class {
 
   /**
    * Checks if a byte has odd parity (Odd number of 1s in binary).
-   * @param {!number} byte
-   * @return {!boolean} True if the byte has odd parity.
+   * @param {number} byte
+   * @return {boolean} True if the byte has odd parity.
    * @private
    */
   isOddParity_(byte) {
@@ -376,29 +376,29 @@ shaka.cea.CeaDecoder = class {
 
 /**
  * itu_t_35_provider_code for ATSC user_data
- * @private @const {!number}
+ * @private @const {number}
  */
 shaka.cea.CeaDecoder.ATSC_PROVIDER_CODE = 0x0031;
 
 /**
  * When provider is ATSC user data, the ATSC_user_identifier code
  * for ATSC1_data is "GA94" (0x47413934)
- * @private @const {!number}
+ * @private @const {number}
  */
 shaka.cea.CeaDecoder.ATSC1_USER_IDENTIFIER = 0x47413934;
 
 /**
- * @private @const {!number}
+ * @private @const {number}
  */
 shaka.cea.CeaDecoder.NTSC_CC_FIELD_1 = 0;
 
 /**
- * @private @const {!number}
+ * @private @const {number}
  */
 shaka.cea.CeaDecoder.NTSC_CC_FIELD_2 = 1;
 
 /**
  * 0xB5 is USA's code (Rec. ITU-T T.35)
- * @private @const {!number}
+ * @private @const {number}
  */
 shaka.cea.CeaDecoder.USA_COUNTRY_CODE = 0xb5;