Make minimal changes to add a new build configuration

app/build.gradle

@@ -102,6 +102,13 @@ android {
                     "deepLinkScheme": deepLinkSchemeValue
             ]
         }
+        forkDebug {
+            shrinkResources false
+            minifyEnabled false
+            applicationIdSuffix ".fenix.debug"
+            resValue "bool", "IS_DEBUG", "true"
+            pseudoLocalesEnabled true
+        }
     }
 
     aaptOptions {
@@ -142,6 +149,9 @@ android {
             java.srcDirs = ['src/migration/java', 'src/geckoRelease/java']
             manifest.srcFile "src/migration/AndroidManifest.xml"
         }
+        forkDebug {
+            java.srcDirs = ['src/geckoNightly/java']
+        }
     }
 
     splits {
@@ -316,6 +326,7 @@ apply plugin: "org.mozilla.telemetry.glean-gradle-plugin"
 
 dependencies {
     debugImplementation Deps.mozilla_browser_engine_gecko_nightly
+    forkDebugImplementation Deps.mozilla_browser_engine_gecko_nightly
 
     nightlyImplementation Deps.mozilla_browser_engine_gecko_nightly
     betaImplementation Deps.mozilla_browser_engine_gecko_beta
@@ -529,6 +540,9 @@ if (project.hasProperty("coverage")) {
             debug {
                 testCoverageEnabled true
             }
+            forkDebug {
+                testCoverageEnabled true
+            }
         }
     }
 }

app/src/main/java/org/mozilla/fenix/Config.kt

@@ -6,6 +6,7 @@ package org.mozilla.fenix
 
 enum class ReleaseChannel {
     Debug,
+    ForkDebug,
     Nightly,
     Beta,
     Release;
@@ -13,6 +14,7 @@ enum class ReleaseChannel {
     val isReleased: Boolean
         get() = when (this) {
             Debug -> false
+            ForkDebug -> false
             else -> true
         }
 
@@ -39,7 +41,7 @@ enum class ReleaseChannel {
         get() = this == Beta
 
     val isNightlyOrDebug: Boolean
-        get() = this == Debug || this == Nightly
+        get() = this == Debug || this == Nightly || this == ForkDebug
 
     /**
      * Is this a build for a release channel that we used to ship Fennec on?
@@ -60,6 +62,7 @@ object Config {
         "nightly" -> ReleaseChannel.Nightly
         "beta" -> ReleaseChannel.Beta
         "release" -> ReleaseChannel.Release
+        "forkDebug" -> ReleaseChannel.ForkDebug
         else -> {
             throw IllegalStateException("Unknown build type: ${BuildConfig.BUILD_TYPE}")
         }