Fix findbugs warnings - make constants final.

build/android/findbugs_filter/findbugs_known_bugs.txt

Index: build/android/findbugs_filter/findbugs_known_bugs.txt
diff --git a/build/android/findbugs_filter/findbugs_known_bugs.txt b/build/android/findbugs_filter/findbugs_known_bugs.txt
index a8cc70a66fd4bd573ba534583da1bbabce8299b8..8bbe96664b5f90c7386567c72f9e7f2df6017735 100644
--- a/build/android/findbugs_filter/findbugs_known_bugs.txt
+++ b/build/android/findbugs_filter/findbugs_known_bugs.txt
@@ -23,11 +23,6 @@ M V EI2: org.chromium.content.browser.LoadUrlParams.setPostData(byte[]) may expo
 M V EI: org.chromium.chrome.browser.ChromeBrowserProvider$BookmarkNode.favicon() may expose internal representation by returning ChromeBrowserProvider$BookmarkNode.mFavicon  At ChromeBrowserProvider.java
 M V EI: org.chromium.chrome.browser.ChromeBrowserProvider$BookmarkNode.thumbnail() may expose internal representation by returning ChromeBrowserProvider$BookmarkNode.mThumbnail  At ChromeBrowserProvider.java
 M V EI: org.chromium.content.browser.LoadUrlParams.getPostData() may expose internal representation by returning LoadUrlParams.mPostData  At LoadUrlParams.java
-M V MS: org.chromium.content.browser.LoadUrlParams.LOAD_TYPE_BROWSER_INITIATED_HTTP_POST should be package protected  In LoadUrlParams.java
-M V MS: org.chromium.content.browser.LoadUrlParams.LOAD_TYPE_DATA isn't final and can't be protected from malicious code   In LoadUrlParams.java
-M V MS: org.chromium.content.browser.LoadUrlParams.LOAD_TYPE_DEFAULT should be package protected  In LoadUrlParams.java
-M V MS: org.chromium.content.browser.LoadUrlParams.UA_OVERRIDE_INHERIT should be package protected  In LoadUrlParams.java
-M V MS: org.chromium.content.browser.LoadUrlParams.UA_OVERRIDE_TRUE isn't final and can't be protected from malicious code   In LoadUrlParams.java
 M M LI: Incorrect lazy initialization of static field org.chromium.chrome.browser.sync.ProfileSyncService.sSyncSetupManager in org.chromium.chrome.browser.sync.ProfileSyncService.get(Context)  At ProfileSyncService.java
 M B OS: org.chromium.tools.binary_size.Addr2LineWorkerPool$Addr2LineWorker$Addr2LineTask.run() may fail to close stream  At Addr2LineWorkerPool.java
 M B RV: Exceptional return value of java.io.File.mkdirs() ignored in new org.chromium.tools.binary_size.NmDumper$Output(NmDumper)  At NmDumper.java